Spontaneous vaginal delivery: a risk factor for Erb's palsy?

Abstract

Our purpose was to determine whether Erb's palsies occurring in the absence of shoulder dystocia differ from those occurring after shoulder dystocia. We compared the time course of resolution and incidence of persistent injury at 1 year of age in 17 cases of Erb's palsy without shoulder dystocia and 23 cases associated with shoulder dystocia. The rate of persistence at 1 year was significantly higher in those Erb's cases without identified shoulder dystocia, 7 of 17 (41.2%) versus 2 of 23 (8.7%), p = 0.04. These cases of Erb's palsies also took longer to resolve (6.4 +/- 0.9 vs 2.6 +/- 0.7 months, p = 0.002), had a higher rate of associated clavicular fracture (12 of 17 vs 5 of 23, p = 0.006), and were more likely to occur in the posterior arm (10 of 15 vs 4 of 21, p = 0.009). Erb's palsy occurring without shoulder dystocia may be a qualitatively different injury than that occurring with shoulder dystocia.