Shoulder dystocia and birth trauma in gestational diabetes: a five-year experience.

Over a 5-year period, 210 patients with gestational diabetes mellitus were delivered of offspring weighing greater than or equal to 3500 gm. Only three primary cesarean sections were performed electively because of suspected macrosomia. One hundred twenty patients were delivered vaginally. There were 15 shoulder dystocias but only one permanent brachial plexus injury. Seven of the 15 shoulder dystocias occurred in offspring weighing less than 4000 gm. Of variables examined, only the use of forceps was clearly associated with an increased risk of shoulder dystocia (odds ratio, 5.1). A policy to deliver by cesarean section all fetuses estimated to weigh greater than 4000 gm would considerably increase the number of cesarean sections with minimal fetal benefit.