Vaginal breech birth — structured SAQ (15 marks)

(a) Contraindications and their mechanical reasoning (4 marks)

One mark for naming any four contraindications (half-mark each to a maximum of two marks), and one mark each for the mechanical reasoning behind two of them. ^[1]

The RANZCOG C-Obs 11 contraindications to planned vaginal breech birth, which you should be able to write out verbatim: ^[1]

• Cord presentation.
• Fetal growth restriction (estimated fetal weight below the 10th centile) or macrosomia (estimated fetal weight above 3.8 kg).
• Any presentation other than frank (extended) or complete (flexed) breech — footling and incomplete breech are out.
• Hyperextension of the fetal neck on ultrasound.
• Evidence of antenatal fetal compromise, for example an abnormal CTG.
• A fetal anomaly incompatible with vaginal birth.^[1]

Mechanical reasoning (any two, one mark each): ^[1]

• Footling breech does not plug the pelvis — the narrow presenting part leaves room for the cord to prolapse, and the cervix is often incompletely dilated when the trunk arrives, so the after-coming head is entrapped.
• Hyperextended neck ("star-gazing") presents the occiput and the largest head diameter to an undilated cervix and risks cervical spine injury; the head cannot deliver in flexion.
• Macrosomia above 3.8 kg risks head entrapment because the after-coming head is the largest, least compressible part and has not itself prepared the pelvis.
• Growth restriction below the 10th centile is a marker of a compromised fetus with reduced reserve for the hypoxic stress of cord compression once the umbilicus delivers.^[1][5]

(b) Conduct of the active second stage (4 marks)

One mark each for: hands-off principle, keeping the back anterior, selective episiotomy, and the team and theatre preparation; one mark for stating the two clocks. ^[1][6]

• Hands off. Let the breech, trunk and body deliver by maternal effort alone. Do not pull. Traction is the parent of nuchal arms, neck extension and head entrapment. When you must hold the fetus, grasp the pelvic girdle over the bony hips — never the abdomen or soft tissues, which risks liver, kidney and adrenal injury — and never hyperextend the neck.^[1]
• Keep the back anterior. RANZCOG C-Obs 11 advises that if the back starts to rotate posteriorly, gentle rotation without traction should be used to keep it anterior. With a back-posterior fetus the chin catches above the symphysis, the head extends rather than flexes, and a deliverable head becomes a stuck one.^[1]
• Selective, not routine, episiotomy when the perineum obstructs the delivering trunk.^[1]
• Team and theatre: senior obstetrician present for the whole second stage, anaesthetist aware, neonatal team in the room, theatre immediately available.^[1]
• The two clocks: intervene to expedite if there is poor fetal tone, or if more than 5 minutes elapse from buttocks to head, or more than 3 minutes from umbilicus to head.^[1]

(c) Lövset's manoeuvre for nuchal arms (4 marks)

One mark for naming Lövset, one mark for the rotation technique, one mark for the second arm, and one mark for stating that the arms come before the head and that traction is never used. ^[1]

1. Name the manoeuvre: Lövset's manoeuvre, the answer for extended or nuchal arms once the scapulae are visible.^[1]
2. Technique for the first arm: hold the fetal pelvis and rotate the trunk through 180 degrees, keeping the back anterior, so that the posterior arm is brought under the pubic arch where it can be swept down by inserting a finger into the antecubital fossa and drawing the arm across the chest.^[1]
3. The second arm: rotate the trunk 180 degrees back in the opposite direction to bring the second (now posterior) arm under the pubic arch and sweep it down in the same way.^[1]
4. Sequence and prohibition: the arms are delivered before the head, and traction is never applied at any point — the head follows by Mauriceau-Smellie-Veit or forceps to the after-coming head, delivered slowly and in flexion.^[1][6]

(d) Term Breech Trial versus PREMODA (3 marks)

One mark for each trial's result, and one mark for the reconciliation (selection is the entire argument). ^[2][3][4]

• Term Breech Trial (Hannah, Lancet 2000): 2088 women randomised; the composite of perinatal mortality, neonatal mortality or serious neonatal morbidity was 1.6% with planned caesarean versus 5.0% with planned vaginal birth (RR 0.33, 95% CI 0.19 to 0.56). This trial changed world practice towards routine caesarean.^[2]
• PREMODA (Goffinet, AJOG 2006): 8105 women in France and Belgium managed under strict selection criteria; the composite neonatal outcome was 1.60% in the planned vaginal group, not significantly different from planned caesarean (adjusted OR 1.40, 95% CI 0.89 to 2.23).^[3]
• The reconciliation: the two trials do not really disagree — PREMODA is a study of selection. The Term Breech Trial included centres without experienced attendants, births without skilled operators, and protocol non-compliance (Glezerman's critiques); PREMODA reproduced good outcomes precisely because it selected strictly and ensured a skilled accoucheur throughout. Selection of fetus, facility and operator is the entire argument.^[4][5]