Permanent Erb's palsy: a lack of a relationship with obstetrical risk factors.

Our objective was to investigate the association between permanent Erb's palsy and the presence of historic obstetrical risk factors. Cases of documented permanent Erb's palsy from our national registry of children with Erb's palsy were extracted and analyzed for the purpose of this descriptive study. Maternal and neonatal records were reviewed for demographic data, prenatal care, labor characteristics, delivery outcome, and long-term follow-up. Sixty-three infants with permanent Erb's palsy were identified. Seventeen (27.0%) mothers were nulliparous. Mean +/- SD (range) gestational age at delivery and birthweight were 39.9 weeks +/- 1.3 (37-43) and 4501 g +/- 625 (3352-6905), respectively. Maternal and perinatal characteristics of these cases were (n [%]): nondiabetic-56 (89%); weight gain <40 lb-48 (76%); normal labor-57 (91%); 2nd stage <2.0 hr-54 (86%); midpelvic procedure-13 (21%); and shoulder dystocia-59 (94%). There were no statistically significant differences between patients with birthweight >4500 g (n = 26 [41%]) and those with birthweight < or =4500 g (n = 37 [59%]). These data suggest that historic risk factors for neonatal brachial plexus injury may not be associated with permanent Erb's palsy.