Shoulder Dystocia

Shoulder dystocia became a leading feature of English (and Scottish) medical law through Montgomery v Lanarkshire Health Board [2015] UKSC 11. Nadine Montgomery, a diabetic mother, faced a 9-10% risk of shoulder dystocia during vaginal delivery — the baby's shoulders being too wide to pass through the mother's pelvis. Her obstetrician did not routinely warn diabetic patients of this risk because, in the doctor's view, the risk of a grave problem for the baby was very small, and warning of shoulder dystocia risk might lead women to opt for a caesarean section, which the doctor did not consider to be in the mother's interest.

The Supreme Court held that the doctor ought to have advised Mrs Montgomery of the substantial risk of shoulder dystocia. The lower courts had focused on the relatively small consequent risk of grave injury to the baby, but the Supreme Court stressed that shoulder dystocia poses various health risks to the woman and baby in its own right, and that shoulder dystocia itself is a major obstetric emergency, so the contrast with the tiny risks of an elective caesarean was stark.

The case is now the leading UK authority on informed consent generally, not just in obstetric cases. The Court held that a doctor is under a duty to take reasonable care to ensure that a patient is aware of any material risks involved in proposed treatment and of reasonable alternatives, replacing the old test (based on Bolam/Sidaway, under which the extent of disclosure was a matter for responsible medical opinion) with a patient-centred test of what a reasonable person in the patient's position would be likely to regard as significant.