A randomized controlled trial of prophylactic maneuvers to reduce head-to-body delivery time in patients at risk for shoulder dystocia. Randomized trial of McRoberts versus lithotomy positioning to decrease the force that is applied to the fetus during delivery.
To assess whether prophylactic use of the McRoberts maneuver and suprapubic pressure decreased the head-to-body time, as a proxy for shoulder dystocia, in at-risk patients.
                Patients with estimated fetal weights over 3800 g were randomized to undergo the McRoberts maneuver and suprapubic pressure before delivery of the fetal head (prophylactic maneuvers) or to undergo maneuvers only after delivery of the head, if necessary (controls). A total of 185 patients were enrolled in the study. After exclusions (eg, abdominal delivery), there were 128 evaluable vaginal deliveries. The study had the power to detect a 30% difference in head-to-body time between groups.
                Head-to-body delivery times did not differ between the prophylactic and control patients (24 +/- 18 seconds versus 27 +/- 20 seconds, P =.38). In addition, the two groups did not differ in rates of admission of the infant to the special care nursery or in birth injuries. There was a significant increase in the risk of delivering by cesarean for patients randomized to the use of prophylactic maneuvers.
                This study does not support the hypothesis that prophylactic use of the McRoberts maneuver and suprapubic pressure speeds delivery in a population of patients at increased risk for shoulder dystocia. In an effort to reduce shoulder dystocia incidence and morbidity, some obstetricians use prophylactic maternal hip hyperflexion (McRoberts maneuver), with the hope of facilitating delivery and decreasing the traction needed for delivery. The objective of this study was to evaluate whether the delivery force is reduced with the prophylactic McRoberts maneuver in a prospective, objective manner.
                Between April 2002 and July 2003, we randomly assigned multiparous women with term, cephalic singleton gestations to delivery in the lithotomy or McRoberts position. A single physician used a force-measuring system that consisted of a custom glove with force sensors to record the amount of force that was exerted on the fetal head. The primary outcomes of the study were peak force (pounds; highest force needed to accomplish entire delivery), peak force for delivery of anterior shoulder (pounds), and peak force rate (pounds per second; the duration required to reach the peak force).
                The peak force was not different between the patients in the lithotomy position (n=13) versus the McRoberts position (n=14; 7.2 +/- 0.8 lbs vs 8.0 +/- 0.7 lbs; P = .5). The peak force for delivery of the anterior shoulder (6.7 +/- 0.8 lbs vs 7.1 +/- 0.7 lbs; P = .7) and peak force rate (32.3 +/- 7.0 lbs/sec vs 29.1 +/- 3.5 lbs/sec; P = .7) were not different between the patients in the lithotomy position versus the McRoberts position, respectively. There was no difference between the groups for gestational age, birth weight, incidence of diabetes mellitus, or operative vaginal delivery. The subjective degree of difficulty of the delivery correlated with the peak force (R2 = 0.53; P = .001).
                The use of the McRoberts maneuver before clinical diagnosis of shoulder dystocia provides no reduction in the force that is used in traction on the fetal head during vaginal delivery in multiparous patients. The acceptance of this maneuver to be used prophylactically requires re-evaluation.
There are no clear findings to support or refute the use of prophylactic manoeuvres to prevent shoulder dystocia, although one study showed an increased rate of caesareans in the prophylactic group. Both included studies failed to address important maternal outcomes such as maternal injury, psychological outcomes and satisfaction with birth. Due to the low incidence of shoulder dystocia, trials with larger sample sizes investigating the use of such manoeuvres are required.