Breech Presentations

Where the the fetus presents "bottom-down" in the uterus.
3 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 due both to pre-existing congenital malformation and increased risk of intrapartum trauma or asphyxia. Caesarian section is now 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.^2,3

The proportion of babies in the breech position declines with gestation: 15% at 30 weeks, 6% at 35 weeks and 3-4% at term. The majority of fetuses turn spontaneously by 36 weeks.

Risk factors for breech presentation⁴

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

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 and also reveal any fetal or uterine abnormalities predisposing to breech presentation.
Refer any suspected breech persisting at 35-36 weeks for scan and specialist opinion.

Reducing the incidence of breech presentation at term

The Royal College of Obstetricians and Gynaecologists (RCOG)³ currently recommends that all women with an uncomplicated breech pregnancy at term (37-42 weeks) should be offered external cephalic version (ECV). ECV reduces the risk of caesarian section in women who intend to undergo ECV without increasing risk to the baby. Success rates of conversion to cephalic presentation vary between 46 to over 80%. Adverse outcomes related to ECV are rare - with no increased risk of antepartum fetal death and only a non-significant increase in onset of labour within 24 hours and nuchal cord found in one systematic review.⁵

Factors contributing to successful ECV include: multiparity, adequate liquor volume and a station above the pelvic brim.
ECV is usually attempted at 37 weeks and should only be carried out by appropriately trained practitioners where facilities for continuous fetal monitoring, ultrasound and emergency caesarian delivery are available. The fetal bottom is lifted with one hand and the fetal head pushed down with the other, moving the fetus in an anticlockwise direction. If fetal heart rate falls below 90 bmp, the attempt should be abandoned.

Tocolysis (use of drugs to decrease uterine tone) appears to improve ECV success rates.⁶
Insufficient evidence exists to support the use of postural techniques (such as knee to chest)⁷ or moxibustion (the burning of chinese herbal medicine on acupuncture points) ⁸ as alternatives to ECV.

Mode of delivery

The main decision is whether to attempt vaginal delivery or plan an elective Caesarian section. The following decision-tree is suggested:³

Preterm breech - vaginal delivery

There is insufficient evidence to support routine Caesarian section for preterm breeches. The poor outcomes for very low birthweight infants are mainly associated with complications of prematurity rather than mode of delivery.

Term breech- planned elective Caesarian section

The Term Breech Trial (international multicentre RCT of planned vaginal delivery versus planned elective caesarian section)⁹ confirmed that vaginal delivery was more hazardous than elective Caesarian section. 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). Longer term maternal and infant outcomes were not examined. The study's results rapidly dictated a new standard of care for breech deliveries but this remains controversial¹⁰ and there have been criticisms of the trial's methods and the attribution of the neonatal deaths and morbidity to mode of delivery.¹¹

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.

• Continuous fetal monitoring is recommended and fetal blood sampling from the buttocks allows accurate assessment of the acid-base status where the fetal heart rate trace is suspect.
• Epidural anaesthetic avoids pushing before full dilation and permits emergency operative intervention.
• Elective episiotomy is usual.
• 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. Arms sometimes need sweeping across the fetal chest.
• 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).
  • Forceps delivery.
  • Burns-Marshall method (feet are grasped and with gentle traction swept in a slow arc over the maternal abdomen).
• Avoid extreme elevation of the body as this may cause hyperextension of the cervical spine.

• Premature rupture of membranes and premature labour
• Cord prolapse (higher risk with footling or complete breech)
• Over rapid descent of after-coming head leading to rapid compression/decompression causing intracranial haemorrhage
• 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).

Pre-term breech births (<2500g) and large post-mature babies (>3500g) have mortality of 12% in absence of other complications. Mature fetuses with normal weight have mortality of 1%. Main problems are intracranial haemorrhage, asphyxia and fractures of the humerus, femur or clavicle.

Breech presentation is associated with an increased risk of abnormalities especially congenital dysplasia of the hip - CDH (newborn risk for boys of 26/1000 and for girls, 120/1000). Extra attention should be paid at the new born and 6-8 week examination. Breech babies should be referred to a practitioner experienced in examining for CDH often combined with ultrasound assessment.¹²