Breech Presentations

This occurs when the the fetus presents 'bottom-down' in the uterus. There are three types:¹

1. Breech with extended legs (frank) - 85% cases
2. Breech with fully flexed legs (complete)
3. Footling (incomplete) with one or both thighs extended

The significance of breech presentation is its association with higher perinatal mortality and morbidity when compared to cephalic presentations. This is due both to pre-existing congenital malformation, increased incidence of breech in premature deliveries and increased risk of intrapartum trauma or asphyxia.

Caesarean section has been adopted as the 'normal' mode of delivery for term breech presentations in Europe and the USA, as the consensus is that this reduces the risk of birth-related complications.² In the USA, over 85% of all breech births are now by Caesarean section (up from 14% in 1970).³ Intrapartum and neonatal deaths associated with breech presentation appear to have been declining: one study based on Scottish births between 1985 and 2004 showed a 75% decrease in deaths but the increased use of planned Caesarean section only partially explained the decrease.⁴

The proportion of babies in the breech position declines with gestation: 20% at 28 weeks and 3-4% at term.⁵ The majority of fetuses turn spontaneously by 36 weeks, adopting the 'best fit' position that a normal gravid uterus provides.

Risk factors for breech presentation⁶

• Lax uterus (usually associated with high maternal parity)
• Uterine anomalies (e.g. bicornuate or septate uterus) or tumour
• Placenta praevia
• Abnormal pelvic brim
• Maternal smoking
• Maternal diabetes
• Fetal malformation (e.g. hydrocephalus)
• Multiple pregnancy
• Polyhydramnios or oligohydramnios
• Low birth weight (preterm delivery or intrauterine growth retardation)
• Previous breech delivery

Maternal or fetal mechanical risk factors are only found in between 7-15% of breech deliveries. Recurrence of breech delivery in successive siblings is high and there appears to be an increased risk of intergenerational recurrence, equally high transmitted via fathers or mothers.⁷

Prior to 32-35 weeks, the diagnosis is of no clinical significance.
Thereafter, clinically:

• Subcostal tenderness
• Ballottable head in the fundal area
• Softer irregular mass in the pelvis
• Fetal heartbeat loudest above the umbilicus
• On VE in labour, sacrum, anus or foot can be palpated through the fornix

Diagnosis is confirmed by ultrasound which can also reveal any fetal or uterine abnormalities predisposing to breech presentation.

Reducing the incidence of breech presentation at term

The Royal College of Obstetricians and Gynaecologists (RCOG)⁸ currently recommends that all women with an uncomplicated breech pregnancy at term should be offered external cephalic version (ECV), provided there are no contra-indications. ECV involves the lifting of the fetal bottom with one hand whilst the fetal head is pushed down with the other, moving the fetus in an anticlockwise direction.

Women should be counselled that:⁸

• ECV reduces the chance of breech presentation at delivery (NNT 2) and consequently reduces the risk of having a Caesarean section (NNT 6). Note that labour with a cephalic presentation after a successful ECV has a higher rate of obstetric intervention than labour with a spontaneous cephalic presentation.
• Success rates of ECV range between 30-80%. Factors contributing to successful ECV include: multiparity, non-white race, relaxed uterine tone, adequate liquor volume and a station above the pelvic brim.
• Adverse outcomes related to ECV are rare. Complications associated with ECV include placental abruption, uterine rupture and fetomaternal haemorrhage. However, no increased risk of antepartum fetal death and only a non-significant increase in onset of labour within 24 hours and nuchal cord was found in one systematic review.⁹
• ECV is offered from 36 weeks in nulliparous women and 37 weeks in multiparous women. ECV can be attempted in post-date women and can even be performed in early labour provided membranes are intact.
• Contra-indications (such as having another indication for Caesarean delivery, antepartum haemorrhage in the last week, abnormal cardiotography (CTG) trace, major uterine anomaly, ruptured membranes) occur in only 4% of women with breech presentation at term.
• Spontaneous reversion to breech presentation after a successful ECV occurs in fewer than 5%.
• It should only be carried out by appropriately trained practitioners where facilities for continuous fetal monitoring, ultrasound and emergency Caesarean delivery are available.
• Women should be advised that ECV can be painful (high pain levels reported in 5%) and the procedure will be stopped if they wish.
• Tocolysis (use of drugs to decrease uterine tone) appears to improve ECV success rates¹⁰ and their use should be considered when an initial attempt at ECV without them has failed.
• Insufficient evidence exists to support the use of postural techniques (such as knee to chest)¹¹ or moxibustion (the burning of chinese herbal medicine on acupuncture points) ¹² as alternatives to ECV.

Mode of delivery

The main decision is whether to attempt vaginal delivery or plan an elective Caesarean section. RCOG guidelines suggests women should be counselled fully regarding the planned mode of delivery and that advice should be based on currently available evidence:⁵

• Planned Caesarean section reduces the risk of perinatal death and early neonatal morbidity in breech babies at term, compared to those born by planned vaginal delivery.
• Delivery mode does not appear to alter the longer-term health of these babies.
• Planned Caesarean section carries a small increased risk of serious intrapartum complications for the mother compared to planned vaginal delivery but does not carry any additional risk to their long-term health outside of pregnancy.
• The long-term effects on future pregnancy outcomes (for both women and their babies) of planned Caesarean section for breech presentation are not certain. Previous Caesarean section carries an increased risk of scar dehiscence in any subsequent pregnancy, of repeat Caesarean section and placenta accreta.
• Women with unfavourable clinical features should be advised of the increased risk of planned vaginal delivery to them and their baby.
  

  Unfavourable factors for vaginal breech birth: Other contra-indications to vaginal delivery, such as placenta praevia Contracted pelvis Footling breech Large baby (>3800 g) Growth restricted baby (<2000 g) Hyperextended fetal neck in labour Lack of suitably trained clinician Previous Caesarean section

• Vaginal breech birth should take place in hospital where rapid access to Caesarean section can occur in the event of poor progress in the second stage of labour.
• Routine Caesarean section for preterm breech presentation is not justified by current evidence and mode of delivery should be decided on an individual basis. The very poor outcome for very low birthweight infants with a breech presentation is mainly due to the multiple complications of prematurity rather than method of delivery.

Much of the evidence favouring elective Caesarean section comes from the Term Breech Trial (TBT), an international multicentre RCT of planned vaginal delivery versus planned elective Caesarean section.¹³ Relative risk of perinatal or neonatal mortality or serious neonatal morbidity was reduced by a third by the use of a planned section (RR 0.33, 95% confidence interval 0.19-0.56). However, a follow-up study at 2 years failed to find a significant difference between the two groups in terms of death or developmental delay.¹⁴ Maternal health at 2 years is not significantly different between women who have experienced the two modes of delivery.¹⁵

The TBT's results rapidly dictated a new standard of care for breech deliveries but this has remained controversial.¹⁶ There have been criticisms of the trial's methods (particularly of its selection criteria and inconsistency in women's care) and its attribution of the neonatal deaths and morbidity to mode of delivery.¹⁷ Attempts to quantify the balance between the risks (both immediate to maternal health and to future pregnancies) against the potential benefit to the infant have proved difficult.

Vaginal breech delivery

Vaginal delivery of a breech presentation requires great skill if the fetus is not to be damaged. With the low rate of vaginal breech deliveries in the developed world, experience is being lost. 6% women with breech presentation still have a vaginal breech delivery as they present too late - so units need to retain a high level of preparedness.

• Induction of labour may be considered (given favourable circumstances) but augmentation of labour is not recommended.⁵
• Continuous fetal monitoring should be offered to all women with a breech presentation in labour. Fetal blood sampling from the buttocks is not advised.⁵
• Epidural anaesthetic avoids pushing before full dilation and permits emergency operative intervention. However RCOG guidelines suggest that it should not be routinely advised and that women should have a choice of analgesia.⁵
• RCOG guidelines suggest delivery in the lithotomy position as experience is greatest with this.⁵
• The maxim is "hands off the breech". Avoid beginning extraction of the fetus prior to complete descent - the cervix must be fully dilated and effaced with the infant's umbilicus at the vaginal introitus.
• Legs deliver and a towel is wrapped around the legs and pelvis.
• As the scapulae are delivered, the fetus' back rotates laterally. Avoid traction. Delayed delivery of the arms should be managed by sweeping them across the baby's face and downwards or by the Lovset manoeuvre (rotating the baby to aid delivery of the arms).
• Once the shoulders are delivered, the head rotates typically to the fetal chin posteriorly. Controlled, slow delivery of the after-coming head is essential. The fetal head should be maintained in a flexed position to allow delivery of its smallest diameter. This can be accomplished by:
  • Mauriceau-Smellie-Veit manoeuvre (with fetus resting on hand and forearm, operator's index and middle fingers lift up the fetal maxillary prominences and an assistant applies suprapubic pressure).
  • Burns-Marshall method (feet are grasped and with gentle traction swept in a slow arc over the maternal abdomen).
  • Forceps delivery.
• Avoid extreme elevation of the body as this may cause hyperextension of the cervical spine.
• If conservative methods fail to deliver the after-coming head, symphysiotomy or rapid Caesarean section are advised.⁵

• Premature rupture of membranes and premature labour
• Cord prolapse (higher risk with footling or complete breech)
• Fetal head entrapment
• Overly rapid descent of after-coming head leading to rapid compression/decompression causing intracranial haemorrhage
• Cervical spine injuries associated with hyperextension
• Delay in delivery leading to asphyxia due to cord compression and placental separation
• Traumatic injuries including fractures of humerus, femur or clavicle, brachial plexus injury (Erb-Duchenne palsy)

Preterm breech births (<2500 g) and large post-mature babies (>3500 g) have mortality of 12% in absence of other complications. Mature fetuses with normal weight have mortality of 1%.

Breech presentation is associated with an increased risk of abnormalities, especially developmental dysplasia of the hip (DDH) - newborn risk for boys of 26/1000 and for girls of 120/1000. Extra attention should be paid at the newborn and 6 to 8-week examination. Breech babies should be referred to a practitioner experienced in examining for DDH, often combined with ultrasound assessment.¹⁸