Shoulder dystocia is an obstetric emergency that complicates 0.2-3.0% of all vaginal deliveries and can result in serious neonatal injury. Neonatal brachial plexus injuries (BPIs) are the most common neurologic sequelae of shoulder dystocia. Neonatal BPIs typically present as unilateral arm weakness and an asymmetrical Moro response, with impaired active abduction of the ipsilateral arm. The reported incidence of BPI after shoulder dystocia ranges from 4% to 40%. The injury is permanent in about 1 of every 10,000 deliveries.

In a case of shoulder dystocia, skilled and timely execution of 1 or more obstetric maneuvers is required to prevent or mitigate serious neonatal morbidity, including BPI. However, evidence is lacking as to what type and sequence of maneuvers are most effective in relieving shoulder dystocia and which maneuvers optimize outcomes for mother and fetus. McRoberts maneuver and suprapubic pressure are generally recommended as the first interventions, with guidelines diverging from there.

To create more room at the perineum and thus, potentially, facilitate delivery, episiotomy has been conventionally recommended by some as an early, standard intervention, and others have even recommended performing a proctoepisiotomy, a deliberate fourth-degree episiotomy. Furthermore, quality assurance reviewers often cite lack of performance of episiotomy during shoulder dystocia delivery resulting in neonatal injury as a criterion for performance improvement. Because neonatal injury resulting from shoulder dystocia is a significant source of litigation, guidelines pertaining to shoulder dystocia interventions also carry legal implications for the obstetrician.

But is performance of an episiotomy a mandatory intervention in cases of shoulder dystocia? In other words, how helpful is the performance of an episiotomy in relieving shoulder dystocia and/or preventing neonatal injury? The theoretical utility of episiotomy is to relieve any obstruction to fetal delivery caused by soft tissue dystocia. However, given that shoulder dystocia is caused by the bony impingement of the anterior fetal shoulder behind the maternal pubic bone, or less commonly, impaction of the posterior shoulder on the sacral promontory, a dystocia of bone rather than soft tissue, many authors have questioned the utility of episiotomy in relieving this obstruction.

We sought to examine the effectiveness of episiotomy in preventing BPI by looking at prevalence trends for shoulder dystocia and BPI at one large, urban hospital over a 10 year period of time when the use of episiotomy, including episiotomy at the time of diagnosed shoulder dystocia, was in decline.