Objective
The objective of the study was to determine whether a decrease in the use of episiotomy was associated with a change in the frequency of brachial plexus injury.
Study Design
All births at Brigham and Women’s Hospital from Sept. 1, 1998, through Aug. 31, 2009, were reviewed. The total number of births, mode of delivery, shoulder dystocias, episiotomies with and without shoulder dystocias, and brachial plexus injuries were recorded. A nonparametric test of trend was performed.
Results
There were a total of 94,842 births, 953 shoulder dystocias, and 102 brachial plexus injuries. The rate of episiotomy with shoulder dystocia dropped from 40% in 1999 to 4% in 2009 ( P = .005) with no change in the rate of brachial plexus injuries per 1000 vaginal births.
Conclusion
Despite historical recommendations for an episiotomy to prevent brachial plexus injury when a shoulder dystocia is encountered, the trend we observed does not suggest benefit from this practice.
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.
Materials and Methods
With the approval of the Partners Institutional Review Board, we conducted a retrospective analysis of all births from Sept. 1, 1998, through Aug. 31, 2009, at Brigham and Women’s Hospital, a teaching hospital and tertiary care facility with a large obstetrics unit. The study center is a large, urban hospital with care provided by a private obstetrics staff and academic faculty including a midwifery service. Together they serve a demographically diverse population.
Included were all births during the time frame of the study for which electronic discharge codes were available. The number of births, mode of delivery, occurrence of shoulder dystocias, and performance of episiotomy with shoulder dystocias were recorded by the primary obstetric caregiver, which was either an attending or resident physician or a midwife. The primary outcome of interest was the occurrence of brachial plexus injury, as diagnosed and reported by the pediatric team at the time of delivery. Maternal records were reviewed for the diagnosis codes of shoulder dystocia, episiotomy, and brachial plexus injury. A Wilcoxon-type test for trend was performed for statistical analysis of the data.
Results
For the period from Sept. 1, 1998, through Aug. 31, 2009, there were 94,842 total births including 67,949 total vaginal births. During the study period, the overall birth rate increased from 9456 in 1999 to a peak of 9711 in 2001, thereafter decreasing every year except 2007. The cesarean section rate increased every year of the study except 2009, peaking at 34% in 2008 ( P = .003). During this period there were 953 shoulder dystocias and 102 brachial plexus injuries. The rate of shoulder dystocias remained constant, ranging from 1.1% to 1.9% of all vaginal deliveries ( P = .569, Figure 1 ).
The rate of episiotomy with shoulder dystocia dropped from 40% in 1999 to 4% in 2009 ( P = .005, Figure 2 ). There was no change in the rate of brachial plexus injuries per 1000 vaginal births ( P = .531, Figure 3 ).
