anomalies of fetal cephalic presentation

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Chapter 15:  Abnormal Cephalic Presentations

Jessica Dy; Darine El-Chaar

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Malpresentations.

• TRANSVERSE POSITIONS OF THE OCCIPUT
• POSTERIOR POSITIONS OF THE OCCIPUT
• BROW PRESENTATIONS
• MEDIAN VERTEX PRESENTATIONS: MILITARY ATTITUDE
• FACE PRESENTATION
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The fetus enters the pelvis in a cephalic presentation approximately 95 percent to 96 percent of the time. In these cephalic presentations, the occiput may be in the persistent transverse or posterior positions. In about 3 percent to 4 percent of pregnancies, there is a breech-presenting fetus (see Chapter 25 ). In the remaining 1 percent, the fetus may be either in a transverse or oblique lie (see Chapter 26 ), or the head may be extended with the face or brow presenting.

Predisposing Factors

Maternal and uterine factors.

Contracted pelvis: This is the most common and important factor

Pendulous maternal abdomen: If the uterus and fetus are allowed to fall forward, there may be difficulty in engagement

Neoplasms: Uterine fibromyomas or ovarian cysts can block the entry to the pelvis

Uterine anomalies: In a bicornuate uterus, the nonpregnant horn may obstruct labor in the pregnant one

Abnormalities of placental size or location: Conditions such as placenta previa are associated with unfavorable positions of the fetus

High parity

Fetal Factors

Errors in fetal polarity, such as breech presentation and transverse lie

Abnormal internal rotation: The occiput rotates posteriorly or fails to rotate at all

Fetal attitude: Extension in place of normal flexion

Multiple pregnancy

Fetal anomalies, including hydrocephaly and anencephaly

Polyhydramnios: An excessive amount of amniotic fluid allows the baby freedom of activity, and he or she may assume abnormal positions

Prematurity

Placenta and Membranes

Placenta previa

Cornual implantation

Premature rupture of membranes

Effects of Malpresentations

Effects on labor.

The less symmetrical adaptation of the presenting part to the cervix and to the pelvis plays a part in reducing the efficiency of labor.

The incidence of fetopelvic disproportion is higher

Inefficient uterine action is common. The contractions tend to be weak and irregular

Prolonged labor is seen frequently

Pathologic retraction rings can develop, and rupture of the lower uterine segment may be the end result

The cervix often dilates slowly and incompletely

The presenting part stays high

Premature rupture of the membranes occurs often

The need for operative delivery is increased

Effects on the Mother

Because greater uterine and intraabdominal muscular effort is required and because labor is often prolonged, maternal exhaustion is common

There is more stretching of the perineum and soft parts, and there are more lacerations

Tears of the uterus, cervix, and vagina

Uterine atony from prolonged labor

Early rupture of the membranes

Excessive blood loss

Tissue damage

Frequent rectal and vaginal examinations

Prolonged labor

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Fetal Presentation, Position, and Lie (Including Breech Presentation)

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Abnormal fetal lie or presentation may occur due to fetal size, fetal anomalies, uterine structural abnormalities, multiple gestation, or other factors. Diagnosis is by examination or ultrasonography. Management is with physical maneuvers to reposition the fetus, operative vaginal delivery , or cesarean delivery .

Terms that describe the fetus in relation to the uterus, cervix, and maternal pelvis are

Fetal presentation: Fetal part that overlies the maternal pelvic inlet; vertex (cephalic), face, brow, breech, shoulder, funic (umbilical cord), or compound (more than one part, eg, shoulder and hand)

Fetal position: Relation of the presenting part to an anatomic axis; for vertex presentation, occiput anterior, occiput posterior, occiput transverse

Fetal lie: Relation of the fetus to the long axis of the uterus; longitudinal, oblique, or transverse

Normal fetal lie is longitudinal, normal presentation is vertex, and occiput anterior is the most common position.

Abnormal fetal lie, presentation, or position may occur with

Fetopelvic disproportion (fetus too large for the pelvic inlet)

Fetal congenital anomalies

Uterine structural abnormalities (eg, fibroids, synechiae)

Multiple gestation

Several common types of abnormal lie or presentation are discussed here.

Transverse lie

Fetal position is transverse, with the fetal long axis oblique or perpendicular rather than parallel to the maternal long axis. Transverse lie is often accompanied by shoulder presentation, which requires cesarean delivery.

Breech presentation

There are several types of breech presentation.

Frank breech: The fetal hips are flexed, and the knees extended (pike position).

Complete breech: The fetus seems to be sitting with hips and knees flexed.

Single or double footling presentation: One or both legs are completely extended and present before the buttocks.

Types of breech presentations

Breech presentation makes delivery difficult ,primarily because the presenting part is a poor dilating wedge. Having a poor dilating wedge can lead to incomplete cervical dilation, because the presenting part is narrower than the head that follows. The head, which is the part with the largest diameter, can then be trapped during delivery.

Additionally, the trapped fetal head can compress the umbilical cord if the fetal umbilicus is visible at the introitus, particularly in primiparas whose pelvic tissues have not been dilated by previous deliveries. Umbilical cord compression may cause fetal hypoxemia.

Predisposing factors for breech presentation include

Preterm labor

Uterine abnormalities

Fetal anomalies

If delivery is vaginal, breech presentation may increase risk of

Umbilical cord prolapse

Birth trauma

Perinatal death

Face or brow presentation

In face presentation, the head is hyperextended, and position is designated by the position of the chin (mentum). When the chin is posterior, the head is less likely to rotate and less likely to deliver vaginally, necessitating cesarean delivery.

Brow presentation usually converts spontaneously to vertex or face presentation.

Occiput posterior position

The most common abnormal position is occiput posterior.

The fetal neck is usually somewhat deflexed; thus, a larger diameter of the head must pass through the pelvis.

Progress may arrest in the second phase of labor. Operative vaginal delivery or cesarean delivery is often required.

Position and Presentation of the Fetus

If a fetus is in the occiput posterior position, operative vaginal delivery or cesarean delivery is often required.

In breech presentation, the presenting part is a poor dilating wedge, which can cause the head to be trapped during delivery, often compressing the umbilical cord.

For breech presentation, usually do cesarean delivery at 39 weeks or during labor, but external cephalic version is sometimes successful before labor, usually at 37 or 38 weeks.

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Malpresentation, Malposition, Cephalopelvic Disproportion and Obstetric Procedures

26 Malpresentation, Malposition, Cephalopelvic Disproportion and Obstetric Procedures Kim Hinshaw 1,2 and Sabaratnam Arulkumaran 3 1 Sunderland Royal Hospital, Sunderland, UK 2 University of Sunderland, Sunderland, UK 3 St George’s University of London, London, UK Malpresentation, malposition and cephalopelvic disproportion Definitions The vertex is a diamond‐shaped area on the fetal skull bounded by the anterior and posterior fontanelles and laterally by the parietal eminences. Vertex presentation is found in 95% of labours at term and is associated with flexion of the fetal head. Breech, brow, face and shoulder presentations constitute the remaining 5% and are collectively known as malpresentations . Their aetiology is usually unknown, but associations include macrosomia, multiparity, polyhydramnios, multiple pregnancy, placenta praevia, preterm labour, and anomalies of the uterus or pelvis (congenital or acquired, e.g. lower segment fibroids) and more rarely the fetus. The denominator is a laterally sited bony eminence on the presenting part (‘occiput’ for vertex presentation, ‘mentum’ for face, ‘acromium’ for shoulder and ‘sacrum’ for breech). The position of the presenting part is defined by the relationship of the denominator to the maternal bony pelvis. The vertex enters the pelvis in the occipito‐transverse (OT) position and during descent rotates to an occipito‐anterior (OA) position in 90% of cases. This position is associated with a well‐flexed head, allowing the smallest anteroposterior (suboccipito‐bregmatic) and lateral (biparietal) diameters to pass through the pelvis (both 9.5 cm). Malposition occurs when the occiput remains in a tranverse or posterior position as labour progresses. Persistent malposition results in deflexion with a larger anteroposterior diameter presenting (occipito‐frontal 11.5 cm). It is associated with increasing degrees of anterior or posterior asynclitism , with one of the parietal bones preceding the sagittal suture (in posterior asynclitism, the posterior parietal bone leads; Fig. 26.1 ). Significant degrees of asynclitism can result in labour dystocia and a higher risk of operative delivery [1] . Fig. 26.1 Posterior asynclitism of the vertex: posterior parietal bone presenting below the sagittal suture. In most cases, flexion occurs as the vertex descends onto the pelvic floor, leading to correction of the malposition and a high chance of spontaneous delivery. The level of the presenting part should be critically assessed as labour progresses. On abdominal examination, the head should descend until it is no more than 1/5 palpable in the late first stage. On vaginal examination the presenting part is assessed relative to the level of the ischial spines. Care must be taken to assess the level using the lowest bony part . Malposition is associated with increased moulding of the fetal skull and a large caput succedaneum, which may give false reassurance about the true degree of descent. In modern obstetric practice, operative vaginal delivery is not attempted if the leading edge of the skull is above the ischial spines (i.e. above ‘0’ station; Fig. 26.2 ). Fig. 26.2 Level of the presenting part relative to the ischial spines. Malpresentations Breech presentation The incidence of breech presentation varies according to gestation: 20% at 30 weeks falling to 4% by term. The aetiology of most breech presentations at term is unclear but known factors to consider include placenta praevia, polyhydramnios, bicornuate uterus, fibroids and, rarely, spina bifida or hydrocephaly. Types of breech presentation Between 50 and 70% of breech presentations manifest with hips flexed and knees extended (extended breech) Complete (or flexed) breech is more common in multiparous women and constitutes 5–10% at term (hips and knees flexed; Fig. 26.3 ). Incomplete or footling breech (10–30%) presents with one or both hips extended, or one or both feet presenting and is most strongly assoiated with cord prolapse (5–10%). Knee presentation is rare. Fig. 26.3 The common types of breech presentation. Clinical diagnosis may miss up to 20% of breech presentations, relying on identifying the head as a distinct hard spherical hard mass to one or other side under the hypochondrium which distinctly ‘ballots’. In such cases the breech is said to feel broader and an old adage reminds us: ‘Beware the deeply engaged head – it is probably a breech!’ Auscultation may locate the fetal heart above the maternal umbilicus and ultrasound confirmation should be considered. Antenatal management If breech presentation is suspected at 36 weeks, ultrasound assessment is recommended as it allows a comprehensive assessment of the type of breech, placental site, estimated fetal weight, confirmation of normality and exclusion of nuchal cord or hyperextension of the fetal neck. External cephalic version (ECV) is encouraged after 36 or more weeks as the chance of spontaneous version to cephalic presentation after 37 weeks is only 8%. Absolute contraindications are relatively few but include placenta praevia, bleeding within the last 7 days, abnormal cardiotocography (CTG), major uterine anomaly, ruptured membranes and multiple pregnancy [2] . Couples should receive counselling about the procedure and its success rates and complications, and the subsequent management of persistent breech presentation. Tocolysis increases the likelihood of success, with average rates of 50% (range 30–80%). Women should be made aware that even with a cephalic presentation following ECV, labour is still associated with a higher rate of obstetric intervention than when ECV has not been required. ECV should be performed in a setting where urgent caesarean section (CS) is available in case of fetal compromise during or soon after ECV. CTG for 30–40 min prior to and after ECV should provide confirmation of fetal health. The chance of success is greater with multiparity, flexed breech presentation and an adequate liquor volume. The use of moxibustion at 33–35 weeks, in combination with acupuncture, may reduce the numbers of births by CS. Training specialist midwives is potentially cost‐efficient with success rates comparable to consultant‐led services (51–66%) [3] . The first step in ECV involves disengaging the breech by moving the fetus up and away from the pelvis, shifting it to a sideways position, followed by a forward somersault to move the head to the lower pole; if this fails a backward somersault can be tried. The need for emergency delivery by CS because of suspected fetal compromise is estimated to be 0.5%. Mothers who are rhesus‐negative should have a Kleihauer–Betke test after the procedure and receive anti‐D. If ECV is unsuccessful, women who are keen to avoid CS may be offered a repeat attempt under neuraxial blockade. This increases the chances of success (58.4% vs. 43.1%; relative risk, RR 1.44, 95% CI 1.27–1.64) and reduces the incidence of CS (46.0% vs. 55.3%; RR 0.83, 95% CI 0.71–0.97) [4] . Otherwise appropriate counselling about the options of elective CS or assisted vaginal breech delivery should be offered. Deciding mode of delivery Despite increasing evidence supporting elective CS for breech delivery at term, controversy and debate continue among professional groups. Breech presentation at term diagnosed antenatally . The Term Breech Trial is the largest published randomized controlled trial where the primary outcome (serious perinatal morbidity and mortality) favoured planned CS over planned vaginal birth: 17/1039 (1.6%) versus 50/1039 (5.0%; RR 0.33, 95% CI 0.19–0.56; P <0.0001) [5] . The trial concluded that ‘planned CS is better than planned VB for the term fetus in the breech presentation; serious maternal complications are similar between the groups’. This has significantly changed practice in many countries despite continuing debate and criticism about the trial design and intepretation of outcomes. However, the latest systematic review has confirmed a significant increased perinatal risk associated with planned vaginal birth [6] . Breech at term diagnosed in labour and preterm breech delivery . Observational trials of term breech ‘undiagnosed’ until presentation in labour confirm that this group has a high vaginal delivery rate with relatively low perinatal morbidity. In a similar vein, the evidence to guide best practice for delivery of the preterm breech remains equivocal, decisions often being based on individual interpretation of the data and local custom and practice. Conducting a vaginal breech delivery For women who wish to deliver vaginally, antenatal selection aims to ensure optimal outcome for mother and baby but remains relatively subjective. Women with frank and complete breech presentations (fetal weight <4000 g) encounter minimal problems, while those with footling breech are advised elective CS because of the increased risk of cord prolapse. CT or X‐ray pelvimetry do not appear to improve outcome. Spontaneous onset of labour is preferred and labour management is similar to vertex presentation. Successful outcome depends on a normal rate of cervical dilatation, descent of the breech and a normal fetal heart rate (FHR) pattern. Where progress of labour is poor and uterine contractions are inadequate, oxytocin augmentation can be used juidiciously with early resort to emergency CS if progress remains slow (<0.5 cm/hour), particularly in the late first stage. Epidural anaesthesia prevents bearing down before the cervix is fully dilated and is particularly important for labour with a preterm breech, when there is a real risk of head entrapment in the incompletely dilated cervix if pushing commences too early. For all breech labours, the mother should be encouraged to avoid bearing down for as long as possible. It is best to wait until the anterior buttock and anus of the baby are in view over the mother’s perineum, with no retraction between contractions. Classically, the mother’s legs are supported in the lithotomy position (the alternative upright breech technique is described later). Primigravidae will usually require an episiotomy with appropriate analgesia, although multigravidae can be assessed as the perineum stretches up. The buttocks deliver in the sacro‐tranverse position. The mother should be encouraged to push with contractions, aiming for an unassisted delivery up to and beyond the level of the umbilicus. There is no need to pull down a loop of cord. The accoucheur should sit with hands ready, but resting on their own legs. Assistance is only required if the legs do not deliver. Gentle abduction of the fetal thigh whilst hyperflexing the hip, followed by flexing the lower leg at the knee will release the foot and leg ( Fig. 26.4 ). Fig. 26.4 Delivery of extended legs by gentle abduction of the thigh with hyperflexion at the hip, followed by flexion at the knee: (a) right leg; (b) left leg. When the scapulae are visible with the arms flexed in front of the chest, sweep each arm around the side of the fetal chest to deliver using a finger placed along the length of the humerus. If the scapulae are not easily seen or if the arms are not easily reached, they may be extended above the shoulders. This can be resolved using the Løvset manoeuvre. Hold the baby by wrapping both hands around the bony pelvis, taking care not to apply pressure to the soft fetal abdomen. Rotate the baby 180° to bring the posterior shoulder to the front, i.e. to lie anteriorly ( Fig. 26.5 a). Complete delivery of the anterior arm by gently flexing the baby laterally downwards towards the floor; the arm will deliver easily from under the pubic ramus ( Fig. 26.5 b). Repeat the 180° rotation in the opposite direction, bringing the posterior shoulder to the front, then flex the baby laterally downwards to deliver the second arm. Fig. 26.5 Løvset’s manoeuvre for extended arms: (a) rotation to bring the posterior (left) arm to the front followed by (b) delivery of the left arm (now anterior) from under the pubic ramus. Nuchal displacement (an arm trapped behind the fetal neck) is rare. If the left arm is trapped, the baby will need to be rotated in a clockwise direction to ‘unwrap’ the arm so that it can be reached. If the right arm is involved, anticlockwise rotation is needed. Allow the head to descend into the pelvis, assisted by the weight of the fetus until the nape of the neck is visible under the symphysis pubis. Ensure slow controlled delivery of the head using one of four methods. Mauriceau–Smellie–Veit manoeuvre: two fingers are placed on the maxilla, lying the baby along the forearm. Hook index and fourth fingers of the other hand over the shoulders with the middle finger on the occiput to aid flexion. Apply traction to the shoulders with an assistant applying suprapubic pressure if needed ( Fig. 26.6 ). Burns–Marshall method: grasp the feet, apply gentle traction and swing the baby gently up and over the maternal abdomen until the mouth and nose appear. Forceps are applied to the head from below, with an assistant supporting the baby’s body in the horizontal plane avoiding hyperextension. Kielland’s forceps can be useful as they lack a pelvic curve. Apply traction, bringing the forceps upwards as the mouth and nose appear. The upright breech technique is increasingly popular in midwifery deliveries. Mobility is encouraged with delivery on all fours, sitting (on a birth stool), kneeling, standing or lying in a lateral position. Delivery is spontaneous with no manual assistance in 70% of cases and a reduced incidence of perineal trauma (14.9%). Fig. 26.6 Delivery of the head using the Mauriceau–Smellie–Veit manoeuvre assisted by suprapubic pressure. Entrapment of the aftercoming head This rare complication occurs in two situations. If the fetal back is allowed to rotate posteriorly, the chin may be trapped behind the symphysis pubis. Correction requires difficult internal manipulation to free the chin by pushing it laterally. McRoberts’ manoeuvre and suprapubic pressure may help. Symphysiotomy is a last resort that can increase the available pelvic diameters. In preterm delivery, the body can slip through an incompletely dilated cervix, with resulting head entrapment. If the cervix cannot be ‘stretched up’ digitally, surgical incisions are made in the cervical ring at 2, 6 and 10 o’clock (Dührssen incisions). Head entrapment in the contractile upper segment can occur at CS. Acute tocolysis and/or extension of the uterine incision may be required to release the head. Women should be intimately involved in decisions about mode of breech delivery and the available evidence presented appropriately. A senior midwife or a doctor experienced in assisted breech delivery must be present. As vaginal breech deliveries decline, developing expertise in breech delivery now relies on simulation training and experience of breech delivery at CS. Summary box 26.1 ECV has a high success rate (51–66%) and should be encouraged. Ensure the fetal back does not rotate posteriorly during breech delivery. The most experienced accoucheur available should directly supervise vaginal breech delivery. Brow presentation Brow presentation occurs in 1 in 1500–3000 deliveries. The head is partially deflexed (extended), with the largest diameter of the head presenting (mento‐vertical, 13.5 cm). The forehead is the lowest presenting part but diagnosis relies on identifying the prominent orbital ridges lying laterally. The eyeballs and nasal bridge may just be palpated lateral to the orbital ridges. Position is defined using the frontal bone as the denominator (i.e. ‘fronto‐‘). Persistent brow presentation results in true disproportion, but when diagnosed in early labour careful assessment of progress is appropriate. Flexion to vertex or further extension to face presentation occurs in 50% and vaginal delivery is possible. Cautious augmentation with oxytocin should only be considered in nulliparous patients for delay in the early active phase of labour. If brow presentation persists, emergency CS is recommended. Vaginal delivery of a brow presentation is possible in extreme prematurity. Preterm labour is best managed in the same way as term labour, with delivery by CS if progress slows or arrests. Cord prolapse is more common and, though rare, uterine rupture can occur in neglected labour or with injudicious use of oxytocin. For this reason labour should not be augmented in multigravid patients with a confirmed brow presentation if progress is inadequate. Face presentation Face presentation occurs in 1 in 500–800 labours. The general causes of malpresentation apply for face presentation, but fetal anomalies (neck or thyroid masses, hydrocephalus and anencephaly) should be excluded. The fetal head is hyperextended and the occiput may be felt higher and more prominently on the same side as the fetal spine. However, face presentation is rarely diagnosed antenatally. On vaginal examination in labour, diagnosis relies on feeling the mouth, malar bones, nose and orbital ridges. Position is defined using the chin or mentum as the denominator. The mouth and malar bones form a triangle which can help differentiate face presentation from breech, where the anus lies in a straight line between the prominent ischial tuberosities. Face presentation is often first diagnosed in late labour. The submento‐bregmatic diameter (9.5 cm) is compatible with normal delivery but only with the fetus in a mento‐anterior position (60%) ( Fig. 26.7 ). The same diameter presents with a persistent mento‐posterior position (25%) but this cannot deliver vaginally as the fetal neck is maximally extended. Fetal scalp clips, blood sampling and vacuum extraction are absolutely contraindicated. Forceps delivery from low cavity can be undertaken for mento‐anterior or mento‐lateral positions by an experienced accoucheur but CS may still be required when descent is poor. Fig. 26.7 The anteroposterior submento‐bregmatic diameter of face presentation. Shoulder presentation The incidence of shoulder presentation at term is 1 in 200 and is found with a transverse or oblique lie. Multiparity (uterine laxity) and prematurity are common associations and placenta praevia must be excluded. The lie will usually correct spontaneously before labour as uterine tone increases, although prolapse of the cord or arm is a significant risk if membranes rupture early. For this reason, hospital admission from 38 weeks is recommended for persistent transverse lie. External version can be offered (and may also be considered for transverse lie presenting in very early labour). On vaginal examination, the denominator is the acromium but defining position can be difficult. If membrane rupture occurs at term with the uterus actively contracting, delivery by CS should be undertaken promptly to avoid an impacted transverse lie. If the uterus is found to be moulded around the fetus, a classical CS is recommended to avoid both fetal and maternal trauma. In cases of intrauterine death with a transverse lie, spontaneous vaginal delivery is possible for early preterm fetuses by extreme flexion of the body (spontaneous evolution). However, CS will usually be required beyond mid‐trimester, although a lower segment approach may be used. Malposition and cephalopelvic disproportion In higher‐income countries, cephalopelvic disproportion is usually ‘relative’ and due to persistent malposition or relative fetal size (macrosomia). Classically we consider these problems with regard to the passage, the passenger or the powers, either alone or in combination. The passage Absolute disproportion due to a contracted pelvis is now rare in higher‐income countries unless caused by severe pelvic trauma and this should be known before the onset of labour. Caldwell and Moloy described four types of pelvis: gynaecoid (ovoid inlet, widest transversely, 50%), anthropoid (ovoid inlet, widest anteroposterior, 25%), android (heart‐shaped inlet, funnel‐shaped, 20%) and platypelloid (flattened gynaecoid, 3%). These can influence labour outcome but as pelvimetry is rarely used and clinical assessment of pelvic shape is inaccurate, this rarely influences clinical mangement in labour. The anthropoid pelvis is associated with a higher risk of persistent occipito‐posterior (OP) position and relative disproportion. The passenger and OP malposition Fetal anomalies (e.g. hydrocephalus, ascites) where disproportion may be a problem in labour are usually assessed antenatally and delivery by elective CS considered. Fetal macrosomia is increasing, related to the rising body mass index (BMI) in many pregnant populations. The evidence for inducing non‐diabetic women with an estimated fetal weight above the 90th centile (or >4000 g) in order to reduce cephalopelvic disproportion remains equivocal. Malposition is an increasingly common cause of disproportion and may be related to a sedentary lifestyle. OP position is associated with deflexion and/or asynclitism with a larger diameter presenting. Optimal uterine activity will correct the malposition in 75% of cases. Flexion occurs as the occiput reaches the pelvic floor with long rotation through 135° to an OA position and a high chance of normal delivery. Moulding of the fetal skull and pelvic elasticity (related to changes at the symphysis pubis) are dynamic changes that facilitate progress in labour and delivery. Short rotation through 45° to direct OP can result in spontaneous ‘face to pubes’ delivery, although episiotomy may be required to allow the occiput to deliver. Persistent OP position occurs in up to 25% of cases and is associated with further deflexion. The risk of assisted delivery is high because of relative disproportion as the presenting skull diameters increase. Delivery in the OP position from mid‐cavity (0 to +2 station) requires critical assessment to decide whether delivery should be attempted vaginally or abdominally and is discussed in later sections. The powers Disproportion is intimately related to dystocia and failure to progress in labour. National Institute for Health and Care Excellence (NICE) guidelines recommend that first stage delay is suspected with cervical dilatation of less than 2 cm in 4 hours when forewater amniotomy should be offered. Delay is confirmed if progress is less than 1 cm 2 hours later and oxytocin augmentation should be offered [6] . This shortens labour but does not affect operative delivery rates. High‐dose oxytocin may reduce CS rates but larger trials are required before these regimens are used routinely. The decision to use oxytocin in labour arrest in multigravid patients must only be made by the most senior obstetrician and should always be approached with extreme caution as uterine rupture is a possible consequence. In the second stage, particularly with epidural analgesia, passive descent for at least 1 hour is recommended, and possibly longer if the woman wishes, before encouraging active pushing. With regional analgesia and a normal FHR pattern, birth should occur within 4 hours of full dilatation regardless of parity [7] . Oxytocin may be commenced in nulliparous patients in the passive phase if contractions are felt to be inadequate and particularly with the persistent OP position. Failure of second‐stage descent combined with excessive caput or moulding suggests disproportion and requires critical assessment to decide the appropriate mode of delivery. Summary box 26.2 OP position with deflexion of the head and asynclitism results in relative disproportion compounded by inadequate uterine activity. With epidural analgesia in place, passive descent should be encouraged for at least 1 hour. Augmentation with oxytocin should be used with extreme caution in multigravid patients with labour arrest. Instrumental vaginal deliveries Background The incidence of instrumental vaginal delivery (IVD) varies widely and in Europe ranges from 0.5% (Romania) to 16.4% (Ireland), although there is no direct relationship with CS rates [ 8 , 9 ]. Epidural analgesia is associated with higher IVD rates. Allowing a longer passive second stage for descent results in less rotational deliveries and possibly a reduction in second‐stage CS [ 10 , 11 ]. Common indications for IVD include delay in the second stage of labour due to inadequate uterine activity, malposition with relative disproportion, maternal exhaustion and fetal compromise. Women with severe cardiac, respiratory or hypertensive disease or intracranial pathology may require IVD to shorten the second stage (when forceps may be preferred). Assessment and preparation for IVD The condition of the mother and fetus and the progress of labour should be assessed prior to performing IVD. Personal introductions to the woman and her partner are essential, explaining the reason for IVD and ensuring a chaperone and enough support are available. The findings, plan of action and the procedure itself should be explained and the discussions carefully recorded. Verbal or written consent is obtained. The mother and her partner may be physically and emotionally exhausted and great care should be exercised in terms of behaviour, communication and medical action. On abdominal examination, the fetal head should be no more than 1/5 palpable (preferably 0/5). A scaphoid shape to the lower abdomen may indicate an OP position. The FHR pattern should be assessed, noting any clinical signs of fetal compromise (e.g. fresh meconium). With acute fetal compromise (e.g. profound bradycardia, cord prolapse) delivery must be expedited urgently and this may only allow a brief explanation to be given to the patient and her partner at the time. If contractions are felt to be infrequent or short‐lasting, an oxytocin infusion should be considered in the absence of signs of fetal compromise. Both vacuum and forceps deliveries are associated with an almost threefold increased risk of shoulder dystocia compared with spontaneous delivery and this should be anticipated. However, it remains unclear whether this increased incidence is a cause or effect phenomenon [12] . On vaginal examination the cervix should be fully dilated with membranes absent. The colour and amount of amniotic fluid is recorded. Excessive caput or moulding may suggest the possibility of disproportion. Inability to reduce overlapping skull bones with gentle pressure is designated ‘moulding +++’; overlapping that reduces by gentle digital pressure is ‘moulding ++’, and meeting of the bones without overlap is ‘moulding +’. Identification of position, station, degree of deflexion and asynclitism will help decide whether IVD is appropriate, where it should be undertaken and who should undertake the procedure. Successful IVD is associated with station below the spines and progressive descent with pushing. If the head is 1/5 palpable abdominally, the leading bony part of the head is at the level of the ischial spines (mid‐cavity). When the head is more than 1/5 palpable and/or when station is above the spines, delivery by CS is recommended. Position is determined by identification of suture lines and fontanelles. The small posterior fontanelle (PF) lies at the Y‐shaped junction of the sagittal and lambdoidal sutures but may be difficult to feel when there is marked caput. The anterior fontanelle (AF) is a larger diamond‐shaped depression at the junction of the two parietal and two frontal bones. It can be differentiated from the PF by identifying the four sutures leading into the fontanelle. In deflexion (particularly OP positions) the AF lies centrally and is easily felt. Position can be confirmed by reaching for the pinna of the fetal ear, which can be flicked forwards indicating that the occiput lies in the opposite direction. Reaching the ear suggests descent below the mid‐pelvic strait. The degree of asynclitism should be assessed (see Fig. 26.1 ), with increasing degrees suggesting disproportion and a potentially more difficult IVD. Assessment of level and position can be difficult with OP position and in obesity. If there is any doubt after careful clinical examination, ultrasound assessment is recommended. The fetal orbits are sought and the position of the spine is noted. This is simple to do and can reduce the incorrect diagnosis of fetal position without delaying delivery, although on its own may not reduce morbidity associated with IVD [13] . IVD is normally performed with the mother in the dorsal semi‐upright position with legs flexed and abducted, supported by lithotomy poles or similar. The procedure is performed with good light and ideally aseptic conditions. The vulva and perineum should be cleansed and the bladder catheterized if the woman is unable to void. Adequate analgesia is essential and requires careful individualized assessment. Epidural anaesthesia is advisable for mid‐cavity IVD (i.e. station 0 to +2 cm below the ischial spines; see Fig. 26.2 ). In the absence of a pre‐existing epidural, spinal anaesthesia may be considered. IVD at station +2 cm or below is termed ‘low‐cavity’ and regional or pudendal block with local perineal infiltration (20 mL 1% plain lidocaine) can be used. Outlet IVD is performed when the head is on or near the perineum with the scalp visible without separating the labia. Descent to this level is associated with an OA position requiring minimal or no rotation and perineal infiltration with pudendal anaesthesia is effective. When the vertex is below the spines, IVD is carried out with different types of forceps or vacuum equipment, depending on the position and station of the vertex and the familiarity and experience of the doctor. Overall, comparing outcomes is easier if designation is by station and position at the time of instrumentation (e.g. left OP at +3) rather than simply mid, low or outlet IVD [ 11 , 14 ]. Choice of instruments: forceps or ventouse The choice of instrument depends on the operator’s experience, familiarity with the instrument, station and position of the vertex. Therefore, knowledge of the station and the position of the vertex is essential. The fetus in an OA position in the mid/low cavity can be delivered using non‐rotational, long or short‐handled forceps or a vacuum device: silicone, plastic or anterior metal cups (with suction tubing arising from the dorsum of the cup) are all suitable. For the fetus lying OT at mid‐ or low‐cavity, or lying OP position mid‐cavity, Kielland’s forceps or vacuum devices can be used to correct the malposition. Manual rotation is another technique to consider. Low‐cavity direct OP positions can be delivered ‘face to pubis’ but this may cause signifcant perineal trauma as the occiput delivers. For this reason, an OP vacuum cup (with the suction tubing arising from the edge of the cup) may be preferred. The cup will promote flexion and late rotation to OA often occurs on the perineum just prior to delivery. The Kiwi OmniCup® is an all‐purpose disposable vacuum delivery system with a plastic cup and in‐built PalmPump™ suitable for use in all positions of the vertex. Later models also display force traction to help the accoucheur avoid cup slippage ( http://clinicalinnovations.com/portfolio‐items/kiwi‐complete‐vacuum‐delivery‐system/ ) Forceps delivery Forceps come in pairs and most have fenestrated blades with a cephalic and pelvic curve between the heel and toe (distal end) of each blade. The heel continues as a shank which ends in the handle. The handles of the two blades sit together and meet at the lock. The cephalic curve fits along either side of the fetal head with the blades lying on the maxilla or malar eminences in the line of the mento‐vertical diameter ( Fig. 26.8 a). When correctly attached, uniform pressure is applied to the head, with the main traction force applied over the malar eminences. The shanks are over the flexion point, allowing effective traction in the correct direction. Non‐rotational forceps (the longer‐handled Neville Barnes or Simpson, and the shorter‐handled Wrigley’s) have a distinct pelvic curve that allows the blades to lie in the line of the pelvic axis whilst the handles remain horizontal. Kielland’s forceps have a minimal pelvic curve to allow rotation within the pelvis to correct malposition. Fig. 26.8 (a) Malar forceps application showing mento‐vertical diameter; (b) forceps traction (Pajot’s manoeuvre). Prior to applying forceps, the blades should be assembled to check whether they fit together as a pair. All forceps have matching numbers imprinted on the handles or shanks and these should also be checked. Non‐rotational forceps can be applied when the vertex is no more than 45° either side of the direct OA position (i.e. right OA to left OA). Application and delivery in a direct OP position is also possible but not routinely recommended because of increased perineal trauma. The left blade is inserted first using a light ‘pencil grip’, negotiating the pelvic and cephalic curves with a curved movement of the blade between the fetal head and the operator’s right hand, which is kept along the left vaginal wall for protection. Hands are swapped to insert the right blade using the same technique. Correct application results in the handles lying horizontally, right on top of left, and locking should be easy. Before applying traction, correct application must be confirmed: (i) the sagittal suture is lying midline, equidistant from and parallel to the blades; (ii) the occiput is no more than 2–3 cm above the level of the shanks (i.e. head well‐flexed); and (iii) no more than a fingertip passes into the fenestration at the heel of the blade. From mid‐ and low‐cavity, Pajot’s maneouvre should be used, balancing outward traction with one hand with downward pressure on the shanks with the other ( Fig. 26.8 b, white arrow). The handles are kept horizontal to avoid trauma to the anterior vaginal wall from the toes of the blades. Traction is synchronized with contractions and maternal effort, and the resultant movement is outwards down the line of the pelvic axis until the head is crowning. An episiotomy is usually needed as the perineum stretches up. The direction of traction is now upwards once the biparietal eminences emerge under the pubic arch and the head is born by extension. The mother will usually ask to have her baby handed to her immediately (unless active resuscitation is required). After completing the third stage, any perineal trauma is repaired and a full surgical count completed. The procedure, including plans for analgesia and bladder care, should be fully documented. Rotational forceps Kielland’s forceps have a minimal pelvic curve allowing rotation of the head at mid‐cavity. They are powerful forceps requiring a skilled accoucheur who is willing to abandon the procedure if progress is not as expected. The number of units able to teach use of Kielland’s forceps to the point of independent practice is declining in the UK. The forceps should match and are applied so that the knobs on the handles face the fetal occiput. Kielland’s are used to correct both OT and OP positions using two methods of application. Direct application involves sliding each blade along the side of the head if space permits, and is more easily achieved with OP positions. Wandering application is useful in OT positions. The first blade is applied in front of the fetal face, from where it is gently ‘wandered’ around to lie in the usual position alongside the malar bone. The posterior blade is applied directly using the space in the pelvic sacral curve. If application is difficult or the blades do not easily lock, the procedure should be abandoned. Correct application should be confirmed. Once locked, it is essential to hold the handles at a relatively steep angle downwards in the line of the mid‐pelvic axis in order to achieve easy rotation. Asynclitism is corrected using the sliding lock, moving the shanks over each other until the knobs are aligned. Rotation should take place between contractions, using only gentle force. Rotation may require the fetal head to be gently disimpacted, either upwards or downwards but no more than 1‐cm displacement is needed. Correct application should be checked again after rotation. Traction should result in progressive descent and an episiotomy is usually required. At the point of delivery, the handles of Kielland’s are only just above the horizontal because of the lack of pelvic curve. If there is no descent with traction during three contractions with maternal effort, the procedure should be abandoned. Whether Kielland’s delivery takes place in the delivery room or in obstetric theatre requires careful assessment of fetal and maternal condition, analgesia and labour progress. If there is any doubt, a formal trial of forceps should be arranged. Vacuum delivery Ventouse or vacuum delivery is increasingly favoured over forceps delivery for similar indications in the second stage of labour. The prerequisites to be satisfied before vacuum delivery are the same as for all forms of IVD. Vacuum delivery is contraindicated below 34 +0 weeks and should be used with caution between 34 +0 to 36 +0 weeks [11] . Overall it is contraindicated for fetuses with possible haemorrhagic tendencies (risk of subgaleal haemorrhage) and before full dilatation [11] . Experienced practitioners may consider vacuum after 8 cm in a multigravid patient in some circumstances. There are many types of vacuum cup in regular use, made of different materials and of differing shapes. Whichever cup is used, the aim is to ensure that the centre of the cup is directly over the flexion point. The flexion point is 3 cm in front of the occiput in the midline and is the point where the mento‐vertical diameter exits the fetal skull [15] . Traction on this point promotes flexion, presenting the smallest diameters for descent through the pelvis: this is the optimum flexing median application ( Fig. 26.9 a). Other applications increase the risk of cup detachment, failed vacuum delivery and scalp trauma. In decreasing order of effectiveness, these are the flexing paramedian application ( Fig. 26.9 b), the deflexing median application ( Fig. 26.9 c) and the deflexing paramedian application ( Fig. 26.9 d). Fig. 26.9 Placement of the vacuum cup, from most favourable (a) to unfavourable (d). (a) Flexing median; (b) flexing paramedian; (c) deflexing median; (d) deflexing paramedian. It is vitally important to select the correct cup and this will vary depending on both the position and attitude of the fetus. The soft Silc, Silastic or anterior metal cups (where the tubing is attached on the dorsum of the cup) are not suitable for OT or OP positions, as their shape and configuration do not allow application over the flexion point. They are suitable for OA positions where the flexion point is accessible in the midline. Metal cups come in different sizes, usually 4, 5 or 6 cm in diameter. In a systematic review they were more likely to result in successful vaginal birth than soft cups (RR 1.63, 95% CI 1.17–2.28), but with more cases of scalp injury (RR 0.67, 95% CI 0.53–0.86) and cephalhaematoma (RR 0.61, 95% CI 0.39–0.95) [16] . A specially designed cup should be used for OT and OP positions: metal OP cups have tubing emerging from the lateral aspect of the cup and the Kiwi OmniCup has a groove in the dorsum of the cup to accommodate the flexible stem. These cups can be manoeuvred more laterally or posteriorly to reach the flexion point. Hand‐held vacuum is associated with more failures than metal ventouse [16] , although a larger study suggested that the OmniCup has an overall failure rate of 12.9% [11] . Aldo Vacca (1941–2014) was the doyen of vacuum delivery and (with reference to the flexion point and cup application) his favourite quote was ‘It’s always more posterior than you think’. After ensuring flexion point application, the cup must be held firmly on the fetal scalp, and a finger should be run around the rim to ensure that no maternal tissue is entrapped. A vacuum of 0.2 bar (150 mmHg or 0.2 kg/cm 2 negative pressure) is created using a hand‐held or mechanical pump, before rechecking the position over the flexion point and confirming maternal tissue is not trapped. The vacuum is increased to 0.7–0.8 bar (500–600 mmHg or 0.8 kg/cm 2 ) in one step, waiting 2 min where possible to develop the ‘chignon’ within the cup. Axial traction in the line of the pelvic axis should be timed with uterine contractions and maternal pushing. A thumb should be placed on the cup, with the index finger on the scalp at the edge of the cup allowing the operator to feel any potential detachment before it is heard (by which point it is often too late to prevent detachment). Descent promotes auto‐rotation of the head to the OA position and episiotomy is often not required. Parents should be reassured that the ‘chignon’ will settle over 2–3 days. Manual rotation Manual rotation for persistent OP position is an alternative to IVD. The procedure requires insertion of one hand into the posterior vagina to encourage flexion and rotation. Careful patient selection is essential and the operator must ensure that effective analgesia is in place. The right hand is inserted for a left OP position (insert left hand for right OP). Four fingers are placed behind the fetal occiput to act as the ‘gutter’ on which the head will rotate, with the thumb placed alongside the anterior fontanelle. When the mother pushes with a contraction, the thumb applies pressure to flex the head and rotation to an OA position should occur with minimal effort. In a series ( N  = 61) where OP position was managed in two groups, the spontaneous delivery rate increased from 27% to 77% in the group offered digital rotation ( P <0.0001) [17] . Complications of IVD In a Cochrane review of 32 studies ( N  = 6597), forceps were less likely to fail to achieve a vaginal birth compared with ventouse (RR 0.65, 95% CI 0.45–0.94) [16] . Vaginal and perineal lacerations, including third‐ and fourth‐degree tears, are more common with forceps than with vacuum. Infra‐levator haematomas may occur occasionally and these should be drained if large or symptomatic. The risk of flatus incontinence or altered continence is also higher. Follow‐up of women who have had low or outlet IVD confirms normal physical and neourological outcomes for the vast majority of the newborn. In terms of neonatal outcome, cephalhaematoma is more common with vacuum but risk of facial injury is less. Facial and scalp abrasions are usually minor and heal in a few days. Unilateral facial nerve palsy is rare and resolves within days or weeks and is not usually related to poor technique. Skull fracture is rare and most need no treatment unless depressed, when surgical elevation may be indicated. Vacuum delivery may result in retinal haemorrhages, haematoma confined to one of the skull bones and neonatal jaundice. Severe scalp lacerations imply poor technique and are fortunately rare. Subgaleal haemorrhage may cause minor or severe morbidity and rarely mortality [18] . In reviewing morbidity associated with IVD, it is important to remember that the alternative option of second‐stage CS is also associated with increased morbidity for both mother and baby. Safe practice: sequential intrumentation and trial of instrumental delivery For all IVDs, the procedure should be abandoned if there is ‘no evidence of progressive descent with moderate traction during each contraction, or where delivery is not imminent following three contractions of a correctly applied instrument by an experienced operator’ [11] . Sequential instrumentation is associated with increased neonatal morbidity and the decision to proceed must take into account the relative risks of delivery by second‐stage CS from deep in the pelvis. It can be difficult to judge whether to proceed with IVD, especially in cases with mid‐cavity malposition at the level of the ischial spines. In such cases a trial of instrumental delivery should be undertaken in theatre under regional anaesthesia, with the full theatre team and neonatal practitioner present. The estimated incidence of trial of instrumental delivery is 2–5%. It is vital to maintain awareness of the situation, with a clear willingness to abandon the attempt if progress is not as expected, proceeding immediately to CS. The couple should be advised of this strategy and appropriate consent obtained prior to the procedure, which should be undertaken by the most senior obstetrician available. In the presence of fetal compromise, it is prudent to consider delivery by emergency CS, rather than proceeding with a potentially difficult IVD. Paired cord blood samples should be taken and results recorded after every attempted IVD. Contemporary developments in IVD New methods are being developed to achieve IVD and include disposable plastic forceps with the ability to measure traction force (see http://www.medipex.co.uk/success‐stories/pro‐nata‐yorkshire‐obstetric‐forceps/ and Fig. 26.10 ) and the Odon device where traction is applied using a plastic bag placed around the fetal head and neck. This device is undergoing trials led by the World Health Organization (see http://www.who.int/reproductivehealth/topics/maternal_perinatal/odon_device/en/ ). Fig. 26.10 Pro‐Nata Yorkshire obstetric forceps. Reproduced with permission of Mark Jessup.

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Management of Labour and Delivery – Questions

Rekha Wuntakal, Madhavi Kalidindi, Tony Hollingworth in Get Through , 2014

For each clinical scenario below, choose the single most appropriate stage of labour from the above list of options. Each option may be used once, more than once or not at all. A 30-year-old para 3 woman was admitted at term with regular uterine activity at 5 cm cervical dilatation and 4 hours later she delivered a female neonate with APGARs 9, 10, 10 at 1, 5 and 10 minutes. Syntometrine injection was given immediately after delivery and placenta with membranes was delivered completely 20 minutes after the delivery of the baby by continuous cord traction.A 23-year-old para 3 woman was admitted after spontaneous rupture of membranes at 39 weeks’ gestation. She is contracting 4 in 10 minutes and pushing involuntarily. On vaginal examination the cervix was fully dilated, vertex was 2 cm below the spines in direct occipito-anterior position with minimal caput and moulding.A 30-year-old nulliparous woman was admitted at term with uterine contractions once in every 5 minutes. On examination, the fetus is in cephalic presentation with two fifths palpable per abdomen. The cervix is central, soft, fully effaced and 2 cm dilated with intact membranes.

Biometric Measurements and Normal Growth Parameters in a Child

Nirmal Raj Gopinathan in Clinical Orthopedic Examination of a Child , 2021

In cephalic presentation, the intra-uterine fetal position is of universal flexion, which is carried by the child to the immediate post-partum period. The hips and knees are flexed. The lower legs are internally rotated. The feet are further internally rotated with respect to the lower legs. At times there is an external rotational contracture of the hip that tends to mask the true femoral rotational profile. The anatomy of the lower limbs changes significantly as the child grows. This is primarily in response to the development of motor abilities and the ability of the child to crawl, cruise, stand, walk, and finally run. These changes are seen right from the hip joints, the femoral neck, knees, and tibia to the feet.

DRCOG MCQs for Circuit A Questions

Una F. Coales in DRCOG: Practice MCQs and OSCEs: How to Pass First Time three Complete MCQ Practice Exams (180 MCQs) Three Complete OSCE Practice Papers (60 Questions) Detailed Answers and Tips , 2020

External cephalic version: Used to convert a breech presentation to cephalic presentation.Not contraindicated if there is a prior Caesarean section scar.Can cause premature labour.Contraindicated in hypertension.Can be performed after 33 weeks' gestation in a rhesus-negative mother.

Complex maternal congenital anomalies – a rare presentation and delivery through a supra-umbilical abdominal incision

Published in Journal of Obstetrics and Gynaecology , 2018

Samantha Bonner, Yara Mohammed

She had a spontaneous conception and booked at 9 weeks of gestation under consultant-led care. A scan confirmed the pregnancy was in the right uterus. She had no other significant medical history but did suffer from recurrent urinary tract infections and hence was on low-dose antibiotic prophylaxis. There was no sonographic evidence of hydronephrosis. Her body mass index (BMI) was 18 at the time of booking. Combined screening was low risk and she had a normal 20 week anomaly scan. She had serial growth scans which demonstrated a normal growth trajectory on a customised chart. The baby was consistently a cephalic presentation. She had multidisciplinary antenatal care, including specialist urologists, general surgeons, obstetricians and anaesthetists. An antenatal MRI scan had shown extensive adhesions over the lower segment of the uterus. She was extensively counselled regarding the mode of delivery and this was scheduled at 37 weeks of gestation to avoid the potential of spontaneous labour and an emergency Caesarean section.

Utilization of epidural volume extension technique for external cephalic version

Published in Baylor University Medical Center Proceedings , 2021

Hanna Hussey, James Damron, Mark F. Powell, Michelle Tubinis

Repeat ultrasound demonstrated breech presentation, normal amniotic fluid volume, and fetal head toward the maternal left abdomen. After 0.25 mg of intramuscular terbutaline injection, a forward roll was initiated by applying pressure from behind the fetal head toward the maternal left. Continuous progress was made and bedside ultrasound showed cephalic presentation. Immediately after successful ECV, the fetal heart rate was 70 beats/min but returned to baseline with conservative measures. Motor blockade regressed after approximately 1.5 hours. After 4 hours of fetal heart rate monitoring and tocometry, the patient was deemed stable for discharge. Follow-up discussion with the patient via phone call on postprocedure day 1 confirmed that she was not experiencing pain or concerning symptoms for neuraxial complications. She returned to the labor and delivery unit at 40 weeks’ gestation for elective induction of labor and had a successful vaginal delivery.

Antenatal scoring system in predicting the success of planned vaginal birth following one previous caesarean section

Aida Kalok, Shahril A. Zabil, Muhammad Abdul Jamil, Pei Shan Lim, Mohamad Nasir Shafiee, Nirmala Kampan, Shamsul Azhar Shah, Nor Azlin Mohamed Ismail

The inclusion criteria were pregnant women at 36 weeks of gestation or more with singleton foetus in cephalic presentation, who agreed for trial of vaginal delivery after one lower segment caesarean section. We excluded women with contraindication for vaginal birth, or who declined trial of vaginal delivery from this study. Previous antenatal history was noted and recorded during the 36-week assessment, including year and indication for previous caesarean section. Recurrent indications involved were cephalopelvic disproportion and obstructed labour. While non-recurrent indications were foetal distress and malpresentation. Past operative notes were checked for any operative complications such as extended uterine tear, organ injury and post-partum haemorrhage. Information regarding current pregnancy including pre-existing medical disorder was recorded. Estimated foetal weight based on ultrasound scan at 36 weeks of gestation was used in this study.

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Abnormal Fetal lie, Malpresentation and Malposition

Original Author(s): Anna Mcclune Last updated: 1st December 2018 Revisions: 12

• 1 Definitions
• 2 Risk Factors
• 3.2 Presentation
• 3.3 Position
• 4 Investigations
• 5.1 Abnormal Fetal Lie
• 5.2 Malpresentation
• 5.3 Malposition

The lie, presentation and position of a fetus are important during labour and delivery.

In this article, we will look at the risk factors, examination and management of abnormal fetal lie, malpresentation and malposition.

Definitions

• Longitudinal, transverse or oblique
• Cephalic vertex presentation is the most common and is considered the safest
• Other presentations include breech, shoulder, face and brow
• Usually the fetal head engages in the occipito-anterior position (the fetal occiput facing anteriorly) – this is ideal for birth
• Other positions include occipito-posterior and occipito-transverse.

Note: Breech presentation is the most common malpresentation, and is covered in detail here .

Fig 1 – The two most common fetal presentations: cephalic and breech.

Risk Factors

The risk factors for abnormal fetal lie, malpresentation and malposition include:

• Multiple pregnancy
• Uterine abnormalities (e.g fibroids, partial septate uterus)
• Fetal abnormalities
• Placenta praevia
• Primiparity

Identifying Fetal Lie, Presentation and Position

The fetal lie and presentation can usually be identified via abdominal examination. The fetal position is ascertained by vaginal examination.

For more information on the obstetric examination, see here .

• Face the patient’s head
• Place your hands on either side of the uterus and gently apply pressure; one side will feel fuller and firmer – this is the back, and fetal limbs may feel ‘knobbly’ on the opposite side

Presentation

• Palpate the lower uterus (above the symphysis pubis) with the fingers of both hands; the head feels hard and round (cephalic) and the bottom feels soft and triangular (breech)
• You may be able to gently push the fetal head from side to side

The fetal lie and presentation may not be possible to identify if the mother has a high BMI, if she has not emptied her bladder, if the fetus is small or if there is polyhydramnios .

During labour, vaginal examination is used to assess the position of the fetal head (in a cephalic vertex presentation). The landmarks of the fetal head, including the anterior and posterior fontanelles, indicate the position.

Fig 2 – Assessing fetal lie and presentation.

Investigations

Any suspected abnormal fetal lie or malpresentation should be confirmed by an ultrasound scan . This could also demonstrate predisposing uterine or fetal abnormalities.

Abnormal Fetal Lie

If the fetal lie is abnormal, an external cephalic version (ECV) can be attempted – ideally between 36 and 38 weeks gestation.

ECV is the manipulation of the fetus to a cephalic presentation through the maternal abdomen.

It has an approximate success rate of 50% in primiparous women and 60% in multiparous women. Only 8% of breech presentations will spontaneously revert to cephalic in primiparous women over 36 weeks gestation.

Complications of ECV are rare but include fetal distress , premature rupture of membranes, antepartum haemorrhage (APH) and placental abruption. The risk of an emergency caesarean section (C-section) within 24 hours is around 1 in 200.

ECV is contraindicated in women with a recent APH, ruptured membranes, uterine abnormalities or a previous C-section .

Fig 3 – External cephalic version.

Malpresentation

The management of malpresentation is dependent on the presentation.

• Breech – attempt ECV before labour, vaginal breech delivery or C-section
• Brow – a C-section is necessary
• If the chin is anterior (mento-anterior) a normal labour is possible; however, it is likely to be prolonged and there is an increased risk of a C-section being required
• If the chin is posterior (mento-posterior) then a C-section is necessary
• Shoulder – a C-section is necessary

Malposition

90% of malpositions spontaneously rotate to occipito-anterior as labour progresses. If the fetal head does not rotate, rotation and operative vaginal delivery can be attempted. Alternatively a C-section can be performed.

• Usually the fetal head engages in the occipito-anterior position (the fetal occiput facing anteriorly) - this is ideal for birth

If the fetal lie is abnormal, an external cephalic version (ECV) can be attempted - ideally between 36 and 38 weeks gestation.

• Breech - attempt ECV before labour, vaginal breech delivery or C-section

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A comparison of risk factors for breech presentation in preterm and term labor: a nationwide, population-based case–control study

Anna e. toijonen.

1 Department of Obstetrics and Gynecology, University Hospital (HUS), University of Helsinki, Haartmaninkatu 2, 00290 Helsinki, Finland

3 School of Medicine, University of Helsinki, Helsinki, Finland

Seppo T. Heinonen

Mika v. m. gissler.

2 National Institute for Health and Welfare (THL), Helsinki, Finland

Georg Macharey

To determine if the common risks for breech presentation at term labor are also eligible in preterm labor.

A Finnish cross-sectional study included 737,788 singleton births (24–42 gestational weeks) during 2004–2014. A multivariable logistic regression analysis was used to calculate the risks of breech presentation.

The incidence of breech presentation at delivery decreased from 23.5% in pregnancy weeks 24–27 to 2.5% in term pregnancies. In gestational weeks 24–27, preterm premature rupture of membranes was associated with breech presentation. In 28–31 gestational weeks, breech presentation was associated with maternal pre-eclampsia/hypertension, preterm premature rupture of membranes, and fetal birth weight below the tenth percentile. In gestational weeks 32–36, the risks were advanced maternal age, nulliparity, previous cesarean section, preterm premature rupture of membranes, oligohydramnios, birth weight below the tenth percentile, female sex, and congenital anomaly. In term pregnancies, breech presentation was associated with advanced maternal age, nulliparity, maternal hypothyroidism, pre-gestational diabetes, placenta praevia, premature rupture of membranes, oligohydramnios, congenital anomaly, female sex, and birth weight below the tenth percentile.

Breech presentation in preterm labor is associated with obstetric risk factors compared to cephalic presentation. These risks decrease linearly with the gestational age. In moderate to late preterm delivery, breech presentation is a high-risk state and some obstetric risk factors are yet visible in early preterm delivery. Breech presentation in extremely preterm deliveries has, with the exception of preterm premature rupture of membranes, similar clinical risk profiles as in cephalic presentation.

Introduction

The prevalence of breech presentation at delivery decreases with increasing gestational age. At 28 pregnancy weeks, every fifth fetus lies in the breech presentation and in term pregnancies, less than 4% of all singleton fetuses are in breech presentation at delivery [ 1 , 2 ]. Most likely this is due to a lack of fetal movements [ 3 ] or an incomplete fetal rotation, since the possibility of a spontaneous rotation declines with increasing gestational age. Consequently, preterm labor itself is often associated with breech presentation at delivery, since the fetus was not yet able to rotate [ 4 – 9 ]. This fact makes preterm labor as one of the strongest risk factors for breech presentation.

Vaginal breech delivery in term pregnancies is not only associated with poorer perinatal outcomes compared to vaginal delivery with a fetus in cephalic presentation [ 6 , 10 , 11 ], but also it is debated whether the cause of breech presentation itself is a risk for adverse peri- and neonatal outcomes [ 3 , 12 , 13 ]. Several fetal and maternal features, such as fetal growth restriction, congenital anomaly, oligohydramnios, gestational diabetes, and previous cesarean section, are linked to a higher risk of breech presentation at term, and, furthermore, are associated with an increased risk for adverse perinatal outcomes [ 3 – 5 , 8 , 9 , 14 – 17 ].

The literature lacks studies on the risk factors of breech presentation in preterm pregnancies. It remains unclear whether breech presentation at preterm labor is only caused by the incomplete fetal rotation, or whether breech presentation in preterm labor is also associated with other obstetric risk factors. Most of the studies reviewing risk factors for breech presentation focus on term pregnancies. Our hypothesis is that breech presentation in preterm deliveries is, besides preterm pregnancy itself, associated with other risk factors similar to breech presentation at term. We aim to compare the risks of preterm breech presentation to those in cephalic presentation by gestational age. Such information would be valuable in the risk stratification of breech deliveries by gestational age.

Materials and methods

We conducted a retrospective population-based cross-sectional study. The population included all the singleton preterm and term births, from January 2004 to December 2014 in Finland. The data were collected from the national medical birth register and the hospital discharge register, maintained by the National Institute for Health and Welfare. All Finnish maternity hospitals are obligated to contribute clinical data on births from 22 weeks or birth weight of 500 g to the register. All newborn infants are examined by a pediatrician and given a personal identification number that can be traced in the case of perinatal mortality or morbidity. The hospital discharge register contains information on all surgical procedures and diagnoses (International Statistical Classification of Diseases and Related Health Problems 10th Revision, ICD-10) in all inpatient care and outpatient care in public hospitals.

Authorization to use the data was obtained from the National Institute for Health and Welfare as required by the national data protection law in Finland (reference number THL/652/5.05.00/2017).

The study population included all the women with a singleton fetus in breech presentation at the time of delivery. The control group included all the women with a singleton fetus in cephalic presentation at delivery. Other presentations were excluded from the study ( N  = 1671) (Fig.  1 ). Gestational age was determined according to early ultrasonographic measurement which is routinely performed in Finland and it encompasses over 95% of the mothers, or if not available, to the last menstrual period. We excluded neonates delivered before 24 weeks of gestation and birth weight of less than 500 g, because the lower viability may have influenced the mode of the delivery or the outcome. The study population was divided into four categories according to the World Health Organization (WHO) definitions of preterm and term deliveries. WHO defines preterm birth as a fetus born alive before 37 completed weeks of pregnancy. WHO recommends sub-categories of preterm birth, based on gestational age, as extremely preterm (less than 28 pregnancy weeks), very preterm (28–32 pregnancy weeks), and moderate to late preterm (32–37 pregnancy weeks).

Breech presentation for singleton pregnancies during the period of 2004–2014 in Finland

In our study, we assessed four factors that may be associated with breech presentation based on prior reports [ 3 – 5 , 14 , 17 – 20 ]. These factors were: maternal age below 25 and 35 years or more, smoking, pre-pregnancy body mass index (BMI) over 30, and in vitro fertilization. The following factors were also analyzed: nulliparity, more than three previous deliveries, and history of cesarean section. The obstetric risk factors including maternal hypo- or hyperthyroidism (ICD-10 E03, E05), gestational diabetes (ICD-10 O24.4) and other diabetes treated with insulin (ICD-10 O24.0), arterial hypertension or pre-eclampsia (ICD-10 O13, O14), and maternal care for (suspected) damage to fetus by alcohol or drugs (ICD-10 O35.4, O35.5) were assessed in the analysis. The variables that were also included in the analysis were: oligohydramnios (ICD-10 O41.0), placenta praevia (ICD-10 O44), placental abruption (ICD-10 O45), preterm premature rupture of membranes (PPROM) (ICD-10 O42), infant sex, fetal birth weight below the tenth percentile, fetuses with birth weight above the 97th percentile, and fetal congenital anomalies as defined in the register of congenital malformations.

The babies born in breech presentation from the four study groups were compared with the babies born in cephalic presentation with the equal gestational age, according to WHO classification. The calculations were performed using SPSS 19. Statistical differences in categorical variables were evaluated with the Chi-squared test or Fisher’s exact test when appropriate. We calculated odds ratios (ORs) with corresponding 95% confidence intervals (CIs) using binary logistic regression. Each study group was separately adjusted, according to gestational age at delivery, defined by WHO. The adjustment for the risk factors was done by multivariable logistic regression model for all variables. Differences were deemed to be statistically significant with P value < 0.05.

This analysis includes 737,788 singleton births, from these 20,086 were in breech presentation at the time of delivery. Out of all deliveries, 33,489 infants were born preterm. The prevalence of breech presentation at delivery decreased with the increase of the gestational age: 23.5% in extremely preterm delivery, 15.4% very preterm deliveries, and 6.7% in moderate to late preterm deliveries. At term, the prevalence of breech presentation at delivery was 2.5% (Fig.  1 ).

From all deliveries, 2056 fetuses were born extremely preterm (24 + 0 to 27 + 6 gestational weeks). The differences in the possible risk factors for breech presentation at delivery were higher odds of PPROM (aOR 1.39, 95% CI 1.08–1.79, P  = 0.010) and a lower risk of placental abruption (aOR 0.59, 95% CI 0.36–0.98, P  = 0.040). No statistically significant differences were observed for the other factors (Table ​ (Table1, 1 , Figs.  1 , ​ ,2, 2 , ​ ,3, 3 , ​ ,4 4 ).

Unadjusted and adjusted odds ratios for risk factors in singleton extremely preterm 24 + 0 to 27 + 6 weeks of gestational age fetuses in breech and in cephalic presentations during 2004–2014 in Finland

BMI body mass index, IVF in vitro fertilization, maternal intoxication, PPROM preterm premature rupture of membranes

Prevalence of obstetric risk factors for breech presentation compared to cephalic by gestational age. PPROM preterm premature rupture of membranes, PROM premature rupture of membranes

Obstetric risk factors for breech presentation with adjusted odds ratios by gestational age. PPROM preterm premature rupture of membranes, PROM premature rupture of membranes, aOR adjusted odds ratio

The determinants of breech presentation by gestational age. PPROM preterm premature rupture of membranes, PROM premature rupture of membranes

The group of very preterm deliveries (28 + 0 to 31 + 6 gestational weeks) included 4582 singleton newborns. Breech presentation at delivery was associated with PPROM (aOR 1.61, 95% CI 1.32–1.96, P  < 0.001), oligohydramnios (aOR 1.65, 95% CI 1.03–2.64, P  = 0.038), fetal birth weight below the tenth percentile (aOR 1.57, 95% CI 1.19–2.08, P  = 0.002), and maternal pre-eclampsia and arterial hypertension (aOR 1.31, 95% CI 1.04–1.66, P  = 0.023). Details of risk factors in very preterm breech deliveries are described in Table ​ Table2. 2 . The risk of placenta praevia as well as having a birth weight above the 97th percentile was lower in pregnancies with fetuses in breech rather than in cephalic presentation (Table ​ (Table2, 2 , Figs. ​ Figs.2, 2 , ​ ,3, 3 , ​ ,4 4 ).

Unadjusted and adjusted odds ratios for risk factors in singleton very preterm 28 + 0 to 31 + 6 weeks of gestational age fetuses in breech and in cephalic presentations during 2004–2014 in Finland

BMI body mass index, IVF in vitro fertilization, PPROM preterm premature rupture of membranes

The moderate to late preterm delivery group (32 + 0 to 36 + 6 gestational weeks) included 26,851 deliveries. Breech presentation in moderate to late preterm deliveries was associated with older maternal age (maternal age 35 years or more aOR 1.24, 95% CI 1.10–1.39, P  < 0.001), nullipara (aOR 1.43, 95% CI 1.27–1.60, P  < 0.001), maternal BMI less than 25 (maternal BMI ≥ 25 aOR 0.75, 95% CI 0.62–0.91, P  = 0.004), previous cesarean section (aOR 1.31, 95% CI 1.12–1.53, P  < 0.001), female sex (aOR 1.22, 95% CI 1.11–1.34, P  < 0.001), congenital anomaly (aOR 1.37, 95% CI 1.22–1.55, P  < 0.001), fetal birth weight below the tenth percentile (aOR 1.31, 95% CI 1.10–1.56, P  = 0.003), oligohydramnios (aOR 3.60, 95% CI 2.63–4.92, P  < 0.001), and PPROM (aOR 1.58, 95% CI 1.41–1.78, P  < 0.001). Breech presentation decreased the odds of having a fetus with birth weight above the 97th percentile (aOR 0.60, 95% CI 0.42–0.85, P  = 0.004) (Table ​ (Table3, 3 , Figs. ​ Figs.2, 2 , ​ ,3, 3 , ​ ,4 4 ).

Unadjusted and adjusted odds ratios for risk factors in singleton moderate to late preterm 32 + 0 to 36 + 6 weeks of gestational age fetuses in breech and in cephalic presentations during 2004–2014 in Finland

The term and post-term group included 704,299 deliveries, among them 17,044 fetuses in breech presentation. The factors associated with breech presentation amongst these were: maternal age of 35 years or more (aOR 1.24, 95% CI 1.19–1.29, P  < 0.001), nullipara (aOR 2.46, 95% CI 2.37–2.55, P  < 0.001), maternal BMI less than 25 (BMI ≥ 25 aOR 0.90, 95% CI 0.85–0.96, P  < 0.001), maternal hypothyroidism (aOR 1.53, 95% CI 1.28–1.82, P  < 0.001), pre-gestational diabetes treated with insulin (aOR 1.24, 95% CI 1.00–1.53, P  = 0.049), placenta praevia (aOR 1.45, 95% CI 1.11–1.91, P  = 0.007), premature rupture of membranes (PROM) (aOR 1.58, 95% CI 1.45–1.72, P  < 0.001), oligohydramnios (aOR 2.02, 95% CI 1.83–2.22, P  < 0.001), congenital anomaly (aOR 1.97, 95% CI 1.89–2.06, P  < 0.001), female sex (aOR 1.28, 95% CI 1.24–1.32, P  < 0.001), and birth weight below the tenth percentile (aOR 1.18, 95% CI 1.12–1.24, P  < 0.001) Table ​ Table4 4 includes details for risk factors of term and post-term group (Figs.  2 , ​ ,3, 3 , ​ ,4 4 ).

Unadjusted and adjusted odds ratios for risk factors in singleton term pregnancies in breech and in cephalic presentations during 2004–2014 in Finland

BMI body mass index, IVF in vitro fertilization, PROM premature rupture of membranes

The main novel finding of our study was that the risk associations increase with each gestational age group after 28 weeks of gestation. With the exception of PPROM, the extremely preterm breech deliveries have similar clinical risk profiles as in cephalic presentation when matched for gestational age. However, as gestation proceeds, the risks start to cluster. In moderate to late preterm pregnancies as in term pregnancies, the breech presentation is a high-risk state being associated with several risk factors: PPROM, oligohydramnios, advanced maternal age, nulliparity, previous cesarean section, fetal birth weight below the tenth percentile, female sex, and fetal congenital anomalies. These are in line with the findings of previous studies [ 3 , 5 , 7 , 8 ], that associated breech presentation at term with obstetric risk factors. The prevalence of breech presentation was negatively correlated with the gestational age with a decline from 23.5% in extremely preterm pregnancies to 2.5% at term. The prevalence of breech presentation in preterm pregnancies observed in our trial is similar to that of comparable studies [ 1 , 2 ].

In extremely preterm deliveries, PPROM was the only risk factor for breech presentation and it stayed as a risk for breech presentation through the gestational weeks. This finding is comparable to the previous literature suggesting that PPROM occurs more often at earlier gestational age in pregnancies with the fetus in breech presentation compared with cephalic [ 21 , 22 ]. PPROM might prevent the fetus to change into cephalic presentation. Furthermore, Goodman and colleagues (2013) reported that in pregnancies with a fetus in a presentation other than cephalic had more complications such as oligohydramnios, infections, placental abruption, and even stillbirths. In our study, surprisingly, placental abruption seemed to have a negative correlation with breech presentation among extremely preterm deliveries. This inconsistency between our results and the literature might be due to the small number of cases. Many of the obstetric complications, for example gestational diabetes, late pre-eclampsia, and late intrauterine growth restriction develop during the second or the third trimester of the pregnancy which explains partially why the risk factors for breech presentation are rarer in extremely preterm deliveries.

In very preterm delivery, breech presentation was associated with PPROM, pre-eclampsia, and fetal birth weight below the tenth percentile. Fetal growth restriction is a known risk factor for breech presentation at term, since it is associated with reduced fetal movements due to diminished resources [ 23 – 25 ]. Furthermore, fetal growth restriction is known to be the single largest factor for stillbirth and neonatal mortality [ 26 – 30 ]. Maternal arterial hypertension disturbs placental function which might cause low birth weight [ 31 , 32 ]. Arterial hypertension and pre-eclampsia increased the risk for breech presentation in very preterm births, but not in earlier or later preterm pregnancies. This finding may be due to the bias that pre-eclampsia is a well-described risk factor for PPROM, fetal growth restriction, and preterm deliveries which are also independent markers for breech presentation itself [ 4 , 5 , 31 , 33 , 34 ]. The severity of early pre-eclampsia might affect the fetal wellbeing, reduce fetal movements and growth, which might reduce the spontaneous fetal rotation to the cephalic position [ 35 ]. In addition, the most severe cases might not reach older gestational age before the delivery.

The risk factor for breech presentation in moderate to late preterm breech delivery was PPROM, oligohydramnios, advanced maternal age, nulliparity, previous cesarean section, fetal birth weight below the tenth percentile, female sex, and fetal congenital anomalies. Oligohydramnios is a known significant risk factor for term breech pregnancies [ 25 ] and it is linked to the reduced fetal movements partly due to a restricted intrauterine space [ 24 , 35 ] and nuchal cords [ 35 ]. Additionally, oligohydramnios is associated with placental dysfunction, which might reduce fetal resources and thus has a progressive effect on the fetal movements and prevent the fetus from turning into cephalic presentation [ 3 , 4 , 18 ]. Fetal female sex in moderate to late preterm breech pregnancies remained as a risk factor, as identified previously for term pregnancies [ 3 – 5 ]. It has been debated whether this risk is due to a smaller fetal size or that female fetuses tend to move less [ 9 , 20 ]. The mothers of infants born in breech presentation in moderate to late preterm and term and post-term pregnancies seemed to be older and had an increased risk of having a fetus with a congenital anomaly. The advanced maternal age is associated with negative effects on vascular health, which may have an influence on the developing fetus and increase the incidence of congenital anomalies [ 19 , 34 , 36 ]. Furthermore, congenital anomalies may have a negative influence on fetal movements [ 19 , 35 ]. Whereas, the low birth weight was found as a risk for breech presentation, a birth weight above the 97th percentile was, coherently a protective factor for breech presentation in very to term and post-term pregnancies.

We found that in term pregnancies, breech presentation was associated with advanced maternal age, nulliparity, maternal hypothyroidism, pre-gestational diabetes, placenta praevia, PROM, oligohydramnios, fetal congenital anomaly, female sex of the fetus, and birth weight below the tenth percentile. A previous cesarean section is known to be positively related to the odds of having a fetus in breech presentation at term [ 5 , 14 ], and in our study, this risk factor started to show already in moderate to late preterm pregnancies. Instead of the scar being the cause of breech presentation, it is more likely that the women with a history of breech cesarean section have, during subsequent pregnancies, a fetus in breech presentation again or have a cesarean section for another reason [ 3 , 5 , 37 ]. Our data suggest that the advanced maternal age and nulliparity are the risks for breech presentation at term, but as well as in moderate to late preterm pregnancies. The tight wall of the abdomen and the uterus of nulliparous women might inhibit the fetus from rotating to cephalic presentation [ 9 ]. In a meta-analysis from 2017, older maternal age has been considered to increase the risk of placental dysfunction such as pre-eclampsia and preterm birth [ 36 ] that are also common risk factors for breech presentation [ 4 , 5 ]. Bearing the first child in older maternal age and giving birth by cesarean section may affect the decision not to have another child and might explain the higher rate of nulliparity among moderate to late preterm and term deliveries [ 1 ]. Our study found correlation between maternal hypothyroidism and breech presentation at term. Some studies have demonstrated an association between maternal thyroid hypofunction and adverse pregnancy outcomes such as pre-eclampsia and low birth weight which are, furthermore, risks for breech presentation and may explain partly the higher prevalence of maternal hypothyroidism in term breech deliveries [ 38 – 40 ]. However, the absence of screening of, for example, thyroid diseases may cause bias in the diagnoses.

Our study demonstrated that as gestation proceeds, more obstetric risk factors can be found associating with breech presentation. In the earlier gestation and excluding PPROM, breech deliveries did not differ in obstetric risk factors compared to cephalic. The risk factors in 32 weeks of gestational age are comparable to those in term pregnancy, and several of these factors, such as low birth weight, congenital anomalies and history of cesarean section, are associated with adverse fetal outcomes [ 1 , 4 , 5 , 8 , 14 , 17 ] and must be taken into account when treating breech pregnancies. Risk factors should be evaluated prior to offering a patient an external cephalic version, as the presence of some of these risks may increase the change of failed version or fetal intolerance of the procedure. This study had adequate power to show differences between the risk profiles of breech and cephalic presentations in different gestational phase. Further research, however, is needed for improving the identification of patients at risk for preterm breech labor and elucidating the optimal route for delivery in preterm breech pregnancies.

Our study is unique since it is the first study, to our knowledge, that compares the risks for breech presentation in preterm and term deliveries. The analysis is based on a large nationwide population, which is the major strength of our study. The study population included nearly 34,000 preterm births over 11 years in Finland and 737,788 deliveries overall. The medical treatment of pregnancies is homogenous, since there are no private hospitals treating deliveries. A further strength relates to the important information on the characteristics of the mother, for example smoking during pregnancy and pre-pregnancy body mass index. The retrospective approach is a limitation of the study, another one is the design as a record linkage study, due to which the variables were restricted to the data availability. Therefore, we were not able to assess, for example uterine anomalies or previous breech deliveries to the analysis.

Our results show that the factors associated with breech presentation in very late preterm breech deliveries resemble those in term pregnancies. However, breech presentation in extremely preterm breech birth has similar clinical risk profiles as in cephalic presentation.

Acknowledgements

Open access funding provided by University of Helsinki including Helsinki University Central Hospital.

Abbreviations

Author contribution

AT: Project development, manuscript writing. SH: Project development. MG: Data collection and analysis, manuscript editing. GM: Project development, manuscript editing.

This study was supported by Helsinki University Hospital Research Grants. Authorization to use of the data was obtained from the National Institute for Health and Welfare as required by the national data protection legislation in Finland (reference number THL/652/5.05.00/2017).

Compliance with ethical standards

We declare that we have no conflict of interest.

For this type of study, formal consent is not required. The National Institute for Health and Welfare authorized to use the data (reference number THL/652/5.05.00/2017).

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Anna E. Toijonen, Email: [email protected] .

Seppo T. Heinonen, Email: [email protected] .

Mika V. M. Gissler, Email: [email protected] .

Georg Macharey, Email: [email protected] .

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• Original Article
• Published: 24 October 2013

Breech presentation at delivery: a marker for congenital anomaly?

• D Mostello 1 ,
• J J Chang 2 ,
• C Guild 4 ,
• K Stamps 2 &
• T L Leet 2   na1  

Journal of Perinatology volume  34 ,  pages 11–15 ( 2014 ) Cite this article

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To determine whether congenital anomalies are associated with breech presentation at the time of birth.

Study Design:

A population-based, retrospective cohort study was conducted among 460 147 women with singleton live births using the Missouri Birth Defects Registry, which includes all defects diagnosed during the first year of life. Maternal and obstetric characteristics and outcomes between breech and cephalic presentation groups were compared using χ 2 -square statistic and Student’s t -test. Multivariable binary logistic regression analysis was used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

At least one congenital anomaly was more likely present among infants breech at birth (11.7%) than in those with cephalic presentation (5.1%), whether full-term (9.4 vs 4.6%) or preterm (20.1 vs 11.6%). The relationship between breech presentation and congenital anomaly was stronger among full-term births (aOR 2.09, CI 1.96, 2.23, term vs 1.40, CI 1.26, 1.55, preterm), but not in all categories of anomalies.

Conclusion:

Breech presentation at delivery is a marker for the presence of congenital anomaly. Infants delivered breech deserve special scrutiny for the presence of malformation.

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Acknowledgements

Many thanks go to Gilad Gross, MD for his helpful advice on improving this manuscript. The authors also acknowledge the Missouri Department of Health and Senior Services, Section of Epidemiology for Public Health Practice as the original source of the data. The analysis, interpretations and conclusions in the present study are those of the authors and not the Missouri Department of Health and Senior Services, Section of Epidemiology for Public Health Practice.

Author information

T L Leet: Dr Leet is deceased.

Authors and Affiliations

Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology and Women’s Health, School of Medicine, Saint Louis University, St Louis, MO, USA

Department of Epidemiology, School of Public Health, Saint Louis University, St Louis, MO, USA

J J Chang, F Bai, K Stamps & T L Leet

Department of Biostatistics, School of Public Health, Saint Louis University, St Louis, MO, USA

Department of Pediatrics and the Center for Outcomes Research, School of Medicine, Saint Louis University, St Louis, MO, USA

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Correspondence to D Mostello .

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Presented at the 32nd Annual Meeting of the Society for Maternal-Fetal Medicine, February 6–11, 2012, Dallas, TX, USA.

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Mostello, D., Chang, J., Bai, F. et al. Breech presentation at delivery: a marker for congenital anomaly?. J Perinatol 34 , 11–15 (2014). https://doi.org/10.1038/jp.2013.132

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