Labour characteristics and neonatal Erb's palsy.

ABSTRACT

OBJECTIVE: To determine risk factors for Erb's palsy, with a focus on graphic labour patterns. DESIGN: A case-control study. SETTING: New York City. SAMPLE A total of 45 consecutive cases of Erb's palsy and 90 controls. METHODS: Pregnancies and labours of neonatal Erb's palsy cases were compared with 90 controls using univariate and multiple logistic regression analysis. MAIN OUTCOME MEASURES: Erb's palsy and shoulder dystocia. RESULTS: Mothers of children with Erb's palsy had a higher term body mass index and more gestational diabetes than those of controls. Even cases without diabetes had higher blood glucose values after a 50-g glucose challenge than did controls. Cases had a higher birthweight and a lower ratio of head-to-thoracic circumference than controls. Shoulder dystocia occurred in 67% of cases and in 2% of controls (P = 0.001). Only 46% of labours had a completely normal dilatation pattern. In a multiple logistic regression model, variables independently associated with brachial plexus injury were long deceleration phase of labour, long second stage, high birthweight, black race, and high neonatal or maternal body mass. CONCLUSIONS: Erb's palsy was frequently preceded by abnormal labour and shoulder dystocia; however, a substantial proportion of cases occurred after normal labour and delivery. Predictive models will be necessary to determine to what extent careful monitoring of the terminal portion of dilatation and of fetal descent and incorporation of maternal body mass and race (all independent risk factors in this study) will help identify fetuses at risk for brachial plexus palsy.