Shoulder dystocia--a clinical study of 56 cases.

A retrospective analysis of 17,127 singleton vaginal deliveries revealed 56 cases of shoulder dystocia giving an incidence of 0.3%. Although an increasing incidence of shoulder dystocia was noted as the infant birth-weight increased, 41% of shoulder dystocia occurred in infants of average birth-weight (2,500-3,999g). Diabetes mellitus, postmaturity, maternal weight above 90 kg were each factors associated with a large sized infant which should signal the possible occurrence of shoulder dystocia. In the present series shoulder dystocia occurred in 2.7% of all infants weighing 4,000 g or more. Diabetic women experienced shoulder dystocia more often than non-diabetics. In the diabetics 15.7% of neonates of birth-weight 4,000 g and above sustained shoulder dystocia compared to 1.6% in the nondiabetic patients. Immediate neonatal injury was apparent in 43% of infants with shoulder dystocia, Erb palsy being the commonest injury. The perinatal mortality rate in the series was 54/1,000 deliveries. There was no maternal death. To avoid the potentially lethal and dangerous complications of shoulder dystocia, all clinical and technological methods available should be utilized to detect the excessive sized infants so that abdominal delivery may be performed before it is too late.