Objective definition of shoulder dystocia: a prospective evaluation.

OBJECTIVE: The current study was undertaken to validate the objective definition of shoulder dystocia in a prospectively evaluated group of patients.

STUDY DESIGN: Selected vaginal deliveries from January 1995 to December 1996 (N = 722) were evaluated for head-to-body delivery time and use of ancillary obstetric maneuvers. Charts were reviewed for perinatal and outcome data.

RESULTS: Ninety-nine deliveries were complicated by shoulder dystocia and 623 deliveries had no shoulder dystocia. The objective definition described infants with lower 1-minute Apgar scores and increased birth weight. All fetal injuries were in the shoulder dystocia group. Duration of the second stage was significantly associated with a diagnosis of shoulder dystocia. The risk of shoulder dystocia was increased with maternal diabetes, but it was not correlated with birth weight in diabetics.

CONCLUSIONS: The objective definition of shoulder dystocia identified a group of patients with an increased birth weight and risk of fetal injuries. The use of an objective definition will assist the evaluation of prophylactic and treatment proposals for shoulder dystocia.