Lucan · Conditions

Breech presentation

Australian guidance: RANZCOG C-Obs 11 Breech (2021)

1. Definition and epidemiology

Breech presentation occurs when the foetal buttocks or lower limbs occupy the lower uterine segment rather than the vertex (cephalic) position. It affects 3 to 4 per cent of singleton pregnancies beyond 37 weeks gestation, with the majority detected prior to the onset of labour. Up to 90 per cent of term breech presentations are now delivered by caesarean section in Australia, a shift driven substantially by the Term Breech Trial (Hannah et al., 2000), which demonstrated significantly lower perinatal mortality and serious neonatal morbidity with planned caesarean compared to planned vaginal birth.

2. Pathophysiology

Breech presentation arises from any factor that disrupts the normal process of foetal version, by which the vertex descends into the pelvis during the third trimester. The foetal head is the heaviest and largest pole; under normal circumstances it gravitates toward the fundus early in pregnancy and then rotates downward as the lower uterine segment develops. Conditions that impair this process include uterine anomalies (bicornuate uterus, fibroids), placenta praevia occupying the lower segment, polyhydramnios or oligohydramnios altering the fluid environment permitting or restricting movement, foetal anomalies such as hydrocephalus or anencephaly that alter the size or shape of the presenting pole, and multiparity with reduced uterine tone. Prematurity is strongly associated: the foetus is more likely to be breech the earlier the gestation, as spontaneous version has not yet occurred. In the majority of term cases no underlying cause is identified. The key pathophysiological consequence is that the largest foetal diameter (the head) is delivered last, creating risk of cord prolapse, head entrapment, and hypoxic injury during vaginal birth (Robbins Ch 22).

3. Clinical presentation and diagnostic criteria

Breech presentation is most often detected on routine antenatal abdominal palpation. Leopold manoeuvres reveal a soft, irregular mass in the lower pole (the buttocks) rather than the smooth, hard globular vertex, and the foetal head is palpable at the fundus. The foetal heart is typically auscultated above the umbilicus. Women may report pressure or discomfort in the upper abdomen from the foetal head. Diagnosis by palpation alone carries a non-trivial false positive rate; ultrasound confirmation is therefore mandatory. Three types are recognised: frank (extended) breech (hips flexed, knees extended, most common at term), complete (flexed) breech (hips and knees both flexed), and footling (incomplete) breech (one or both feet presenting). Footling presentation is a contraindication to planned vaginal birth because of increased cord prolapse risk.

4. Investigations and AU-specific cutoffs

Investigations proceed in a structured sequence:

1. Ultrasound confirmation (Recommendation 1, RANZCOG C-Obs 11): performed when breech is suspected on palpation. A detailed obstetric ultrasound should then assess for predisposing factors including foetal anomaly and placenta praevia.
2. Foetal biometry: biparietal diameter, head circumference, abdominal circumference, and femur length to estimate foetal weight. Estimated foetal weight below the 10th centile or greater than 3.8 kg constitutes a contraindication to planned vaginal breech birth.
3. Amniotic fluid volume assessment: oligohydramnios is a relative contraindication to external cephalic version (ECV).
4. Foetal neck assessment: hyperextension of the foetal neck on ultrasound is a contraindication to vaginal breech birth due to spinal cord injury risk.
5. Cardiotocography (CTG): performed before and after ECV; abnormal CTG is an absolute contraindication to proceeding with ECV.
6. MRI pelvimetry: evidence is insufficient to recommend routine use; one study suggested it may reduce emergency caesarean rates but further evidence is required.
7. Rhesus blood group: Rh-negative women require Anti-D immunoglobulin within 72 hours following ECV regardless of outcome (refer RANZCOG C-Obs 6).

5. Management

Management is guided by RANZCOG C-Obs 11 (2021) and depends on gestation, foetal and maternal factors, and patient preference.

External Cephalic Version (ECV) should be offered to all women with a breech presentation at or near term where there are no contraindications (Recommendation 2, Grade A evidence). ECV is recommended from 37+0 weeks in nulliparous women and may be offered from 36+0 weeks given their lower likelihood of spontaneous version. In multiparous women spontaneous version is more common, making earlier offer reasonable. ECV success rates are approximately 40 per cent in nulliparous and 60 per cent in multiparous women. Tocolysis improves success rates and should be used. No more than four attempts are advised, with a maximum of 10 minutes total. ECV must only be performed where emergency caesarean facilities are immediately available (Recommendation 3). Absolute contraindications to ECV include: caesarean indicated on other grounds (e.g. placenta praevia), antepartum haemorrhage within the last 7 days, abnormal CTG, ruptured membranes, rhesus isoimmunisation, and multiple pregnancy (except delivery of the second twin). Postural management and moxibustion are not supported by evidence as methods to achieve version.

Planned caesarean section is recommended for the majority of term breech presentations. Elective caesarean section should be scheduled at 39 weeks gestation in the absence of additional risk factors, in line with RANZCOG C-Obs 23, as breech presentation is associated with increased risk of late-term stillbirth and it may therefore be preferable to deliver before 40 weeks.

Planned vaginal breech birth may be offered to appropriately counselled and selected women in facilities with skilled staff, operating theatre access, continuous electronic foetal monitoring, and immediately available paediatric resuscitation. The decision requires shared decision making (Recommendation 4, Grade C). Induction of labour and augmentation should be avoided. Continuous electronic foetal heart rate monitoring is mandatory throughout labour. A passive second stage is recommended to allow descent; if the breech is not visible within 2 hours of the passive second stage, caesarean section should proceed. Contraindications to planned vaginal breech birth include: cord presentation, foetal weight below the 10th centile or greater than 3.8 kg, any presentation other than frank or complete breech, hyperextension of the foetal neck, evidence of antenatal foetal compromise, and foetal anomaly incompatible with vaginal delivery.

Assisted vaginal breech birth technique. Active pushing should not be encouraged until the breech is visible, and traction should be avoided: the approach is hands-off, with timely intervention if progress stops once the umbilicus has delivered or if the arms are extended. Intervention to expedite birth is required for poor foetal condition (lack of foetal tone), for a delay of more than 5 minutes from delivery of the buttocks to the head, or of more than 3 minutes from the umbilicus to the head. The foetus is grasped around the pelvic girdle rather than soft tissues and the neck is never hyperextended; tactile stimulation is minimised because it can provoke reflex extension of the arms or neck. Episiotomy is selective rather than routine. Once the scapula is visible the arms can be hooked down by inserting a finger at the elbow and flexing them across the chest or, if the arms are nuchal, the Løvset manoeuvre is used (spelled Lovset's manoeuvre in the captured guideline). Delivery is completed with the Mauriceau-Smellie-Veit manoeuvre or with forceps, and suprapubic pressure aids flexion.

Breech first diagnosed in labour: point-of-care ultrasound should be performed, the obstetrician should counsel the woman regarding mode of birth including risks and benefits of emergency caesarean versus attempted vaginal birth, and management should be individualised (Recommendation 7, Grade C).

Preterm breech: when planned preterm delivery is required for maternal or foetal compromise with a viable foetus beyond 25 weeks, elective caesarean section is recommended. Caesarean section for breech at 22+0 to 24+6 weeks is not routinely recommended given no clear neonatal benefit over vaginal birth at this periviable gestation (Recommendation 10, Grade C).

Twin pregnancy with breech presenting twin: planned caesarean section is recommended (Recommendation 11, Grade C).

6. Pharmacology and AU PBS notes

There are no condition-specific medications that constitute definitive treatment of breech presentation. The following pharmacological agents are relevant to management:

Tocolysis for ECV: short-acting tocolytic agents (typically terbutaline 0.25 mg subcutaneous or salbutamol intravenously) are used to improve uterine relaxation and increase ECV success rates. These are not PBS-listed specifically for this indication and are administered in the inpatient procedural setting.

Anti-D immunoglobulin: Rh-negative women must receive Anti-D following ECV regardless of outcome (refer RANZCOG C-Obs 6). In Australia, Anti-D is available as CSL Behring Rho(D) immunoglobulin (RhoGAM equivalent); 625 IU (125 micrograms) intramuscular is the standard dose at or beyond 20 weeks gestation. This is funded through the National Blood Agreement and not billed as a PBS script in the acute inpatient setting.

Regional anaesthesia for caesarean section: spinal or combined spinal-epidural anaesthesia is the preferred technique for elective caesarean section in Australia. No specific PBS codes apply; covered under in-hospital MBS billing.

7. Complications and monitoring

Maternal complications of breech presentation and its management: - Uterine rupture (rare but reported with ECV; 1 in 200 ECV attempts requires emergency caesarean) - Placental abruption following ECV - Increased caesarean section rate and downstream risks including uterine scar rupture in subsequent pregnancies, placenta accreta spectrum, and surgical morbidity from repeat caesarean section

Foetal and neonatal complications: - Cord prolapse: particularly with footling presentation or ruptured membranes - Head entrapment: risk is heightened in preterm vaginal breech (9.3 per cent at 24 to 27 weeks) - Birth trauma: brachial plexus injury, cervical spine injury from neck hyperextension, foetal intracranial haemorrhage - Perinatal asphyxia and hypoxic ischaemic encephalopathy from delayed head delivery - Neonatal death: perinatal death occurred in 1.3 per cent of planned vaginal births versus 0.3 per cent of planned caesarean births in the Term Breech Trial

Monitoring schedule: - Antenatal ultrasound at 36 to 37 weeks if breech presentation detected to confirm and characterise type, assess foetal weight, amniotic fluid, and foetal anomaly - CTG before and after ECV; continuous electronic foetal monitoring during all labour with breech presentation - Post-ECV observation period with CTG and repeat ultrasound to confirm version - Neonatal hip surveillance: breech presentation at term is an independent risk factor for developmental dysplasia of the hip (DDH). Australian guidelines recommend clinical hip examination at birth and follow-up ultrasound at 6 weeks for infants with a history of breech presentation, regardless of mode of delivery - Approximately 3 per cent of successfully versioned babies revert to breech; repeat ultrasound confirmation of presentation at the time of scheduled delivery or onset of labour is therefore recommended

Written for Australian practice and grounded in the guidance named above. Study material only — not medical advice. Always check against current guidelines.