NEW YORK (Reuters Health) – Clinicians faced with a case of shoulder dystocia during childbirth should consider delivering the posterior shoulder after they’ve tried the two primary accepted maneuvers (McRoberts maneuver and suprapubic pressure), clinicians advise in a report in Obstetrics & Gynecology for June.

In a large retrospective study, they found that, after these two maneuvers, delivery of the posterior shoulder was superior to other maneuvers in the acute management of shoulder dystocia with a comparable rate of neonatal injury.

Their study, they say, also confirms that the more maneuvers needed to relieve the shoulder dystocia, the more likely there is to be injury to the neonate.

“The novelty of this study is it is one of the largest studies to look at this issue with an emphasis on the important outcome of neonatal injury,” first author Dr. Matthew Hoffman, of the department of obstetrics and gynecology, Christiana Care Health System, Newark, Delaware, told Reuters Health by e-mail.

Because of the uncommon nature of shoulder dystocia and rarer incidence of neonatal injury, clinicians lack convincing clinical data on how to manage this complication, he noted.

“Our data confirms a number of computer modeling studies that delivery of the posterior shoulder is the most effective choice when compared to other tertiary maneuvers” and that’s “reassuring,” Dr. Hoffman added.

Using an electronic database, Dr. Hoffman and colleagues identified 132,098 women who delivered a term cephalic liveborn fetus vaginally; 2,018 (1.5%) incurred a shoulder dystocia and 101 (5.2%) of these incurred a neonatal injury.

The most common injury was an Erb’s palsy (59.4%) followed by a clavicular fracture (38.6%). There were six cases of hypoxic-ischemic encephalopathy (5.9%). There were no neonatal deaths attributable to shoulder dystocia.

The maneuvers used to resolve shoulder dystocia in the cohort included McRoberts, suprapubic pressure, Rubin maneuver, delivery of the posterior shoulder, Woods corkscrew maneuver, Gaskin maneuver, Zavanelli maneuver and fundal pressure.

On average, each woman required 2 maneuvers to relieve shoulder dystocia.

According to the investigators, 84.4% of deliveries had successful resolution of the shoulder dystocia when delivery of the posterior shoulder was attempted. This is higher than the other maneuvers, which ranged from 24.3% with the McRoberts maneuver to 72.0% for Woods corkscrew.

“Because quick resolution of shoulder dystocia is the primary goal, delivery of the posterior shoulder after the less technically demanding maneuvers of McRoberts and suprapubic pressure would be an appropriate approach,” Dr. Hoffman and colleagues write.

There were no significant differences in rates of neonatal injury with delivery of the posterior shoulder (8.4%) and the other maneuvers (6.1% to 14.0%).

However, the risk of neonatal injury increased with the number of maneuvers performed, which “further strengthens the argument for using the most effective maneuver (delivery of the posterior shoulder) earlier in the approach to cases of shoulder dystocia,” the clinicians say.

Obstet Gynecol 2011;117.