Application of learning theory to obstetric maloccurrence.

The average fellow of the American College of Obstetricians and Gynecologists performs approximately 140 deliveries per year. Based on this estimation and the established prevalence of three commonly litigated maloccurrences, we calculated the number of years of clinical experience required to encounter one case. Permanent brachial plexus palsy complicates only 1 per 4553 deliveries so a clinician would encounter such a case in 33 years of practice. For every 6667 deliveries, there is a case of cerebral palsy attributable to intrapartum hypoxia, so a practioner would see only one case every 48 years. Since the rate of asphyxia with uterine rupture is 1 per 2819 vaginal births after Cesarean section and the average provider performs seven vaginal births after Cesarean deliveries per year, a clinician would have a case in 403 years of practice. Adverse outcomes expressed as an absolute percentage or as the number of cases per number of deliveries are statistically accurate. Expression of these maloccurrences in terms of the number of years of clinical experience permits the generation of a clinically relevant data point and also allows insight into why their prevalence has not decreased.