Shoulder dystocia: What is the risk of recurrence?

Objective. To study the recurrence risk of shoulder dystocia in women who have previously experienced at least once shoulder dystocia. Design. A retrospective study of vaginal deliveries complicated by shoulder dystocia. Setting. American University of Beirut Medical Center - Lebanon. Sample. Vaginal deliveries complicated by shoulder dystocia over a 15-year period who had subsequent vaginal delivery. Methods. Charts of index and subsequent deliveries beyond 24 weeks' gestation were reviewed for demographics and intrapartum events. Women were divided into those with recurrent shoulder dystocia (group I) and those with uncomplicated subsequent delivery (group II) and compared. Main outcome measures. Recurrent shoulder dystocia and characteristics of women with recurrence. Results. The incidence of shoulder dystocia was 0.9% of all vaginal deliveries. Of 193 shoulder dystocia cases, 48 women had a subsequent delivery. After excluding cesarean deliveries (n=4), 44 women were analyzed. Eleven had recurrent shoulder dystocia (25.0%). Mean birthweight was larger (4,019±430 vs. 3,599±398 g, p=0.005) with a higher rate of macrosomia ≥4,000 g (63.6 vs. 15.2%, p=0.004) and the birthweight in the subsequent pregnancy was larger than the index pregnancy in a significantly larger proportion of women in group I compared with group II (72.7% vs. 33.3%, p=0.035). Otherwise, maternal age, gestational age at delivery, parity, duration of labor, gender, history of macrosomia, and interval between pregnancies were similar. Conclusions. The risk of recurrence of shoulder dystocia is around 25%. When counseling women about recurrence risk, the absence of macrosomia and a smaller birthweight than the previous pregnancy could be reassuring.