Obstetric outcome of extreme macrosomia

To determine the effect of extreme macrosomia on perinatal outcome.

We conducted a retrospective review of all deliveries with birth weight > or = 5000 g in a tertiary centre from 1986 to 2000 and analyzed the method of delivery and perinatal outcome.

Extreme macrosomia (birth weight > or = 5000 g) was coded in 111 deliveries. There were 62 deliveries by Caesarean section (CS) (25 in labour and 37 elective). The 49 vaginal deliveries were complicated by 10 (20%) cases of shoulder dystocia and 3 (6%) of Erb's palsy. Permanent Erb's palsy was noted in only 1 of these 3 cases. Shoulder dystocia was associated with use of oxytocin and instrumental deliveries.

Implementing the 2002 guidelines from the American College of Obstetricians and Gynecologists (that is, recommending Caesarean delivery of fetuses with an estimated weight of at least 5000 g) would have a negligible effect on the CS rate while eliminating 10 cases of shoulder dystocia in 49 births. A policy eliminating the use of oxytocin and instrumental deliveries would have prevented most birth traumas in this group. Unfortunately, this high-risk group is difficult to identify in the antepartum period, complicating the implementation of these guidelines and probably leading to higher rates of CS. In addition, the effect of endorsing such a policy on overall neonatal and maternal morbidity is minimal, because most morbidity occurs in newborns weighing less than 4000 g.