Comparing McRoberts' and Rubin's maneuvers for initial management of shoulder dystocia: an objective evaluation.

OBJECTIVE: This study was undertaken to objectively compare delivery traction force, fetal neck rotation, and brachial plexus elongation after 3 different initial shoulder dystocia maneuvers: McRoberts', anterior Rubin's, and posterior Rubin's.

STUDY DESIGN: We developed a laboratory birthing simulator comprised of a maternal model with a 3-dimensional bony pelvis, an instrumented fetal model, a force-sensing glove, and a computer-based data acquisition system. A single operator performed 30 simulated shoulder dystocia deliveries using standard downward traction after 1 maneuver was performed. Ten deliveries simulated McRoberts' maneuver with fetal shoulders in the anteroposterior diameter. Ten deliveries involved approximately 30-degree oblique rotation of the anterior shoulder with the spine oriented anteriorly (anterior Rubin's maneuver). Ten deliveries involved approximately 30-degree rotation of the posterior shoulder to the opposite oblique pelvic diameter, with the spine oriented posteriorly (posterior Rubin's maneuver). Peak traction force, brachial plexus elongation, and neck rotation were compared between groups using analysis of variance, with P < .05 considered significant.

RESULTS: Rubin's maneuvers were found to require less traction force than McRoberts': 16.2 +/- 2.1 lbs for McRoberts' compared with 8.8 +/- 2.2 lbs and 6.5 +/- 1.8 lbs for posterior and anterior Rubin's respectively (P < .0001). Brachial plexus extension was significantly lower after anterior Rubin's maneuver compared with McRoberts' or posterior Rubin's maneuvers. CONCLUSION In a laboratory model of initial maneuvers for shoulder dystocia, anterior Rubin's maneuver requires the least traction for delivery and produces the least amount of brachial plexus tension. Further study is needed to validate these results clinically.