How to predict recurrent shoulder dystocia

Our aim was to determine the rate and risk factors for recurrent shoulder dystocia.

A retrospective analysis of patients diagnosed with shoulder dystocia was performed by searching a computerized database from January 1, 1993, to June 30, 1999 for the following information: (1) vaginal deliveries, either spontaneous or operative, (2) shoulder dystocia, (3) birth weight, (4) duration of second stage of labor, (5) parity, and (6) gestational diabetes. Statistical analyses included chi(2) and t test.

There were 39,681 vaginal deliveries with 602 (1.5%) complicated by shoulder dystocia. Sixty-six patients underwent a subsequent vaginal delivery, and 11 (16.7%) experienced another shoulder dystocia. The odds ratio for a recurrent shoulder dystocia was 10.98 (P <.000001). Nine of the 11 patients with recurrent shoulder dystocia compared with 28 of 55 without a recurrence were nulliparous women in their index pregnancy (P <.001). The mean fetal weights were 3885 g in the recurrent dystocia group and 3702 g in the group without recurrence (P <.03). Gestational age, operative delivery, and gestational diabetes were similar in the two groups.

Factors that appear to increase the recurrence risk of shoulder dystocia include fetal weight and maternal parity. Prior shoulder dystocia is the single greatest predictive factor.