Shoulder dystocia: an obstetric emergency.

Shoulder dystocia is one of the most dreaded complications of vaginal delivery encountered by the obstetrician. Although risk factors for shoulder dystocia exist, approximately 50% of cases do not demonstrate the classic predisposing signs. Obstetricians can help patients decrease their risk for fetal macrosomia by frequent attention to weight gain, nutrition, and exercise during pregnancy and by aggressive management of diabetes. All obstetricians must be familiar with the maneuvers used to effect delivery of impacted shoulders and must be prepared to institute these maneuvers immediately in a crisis situation.