Aims To evaluate maternal ethnicity as a factor reported to increase the risk of shoulder dystocia, and to evaluate its predictive value at a population level.
Methods We conducted a retrospective cohort study of 252 singleton, vertex vaginal deliveries with diagnosed shoulder dystocia born at North Middlesex University Hospital in London, UK. Maternal ethnicity was examined along with maternal characteristics, induction and length of labour, operative vaginal delivery, epidural utilisation, and birth weight. These variables were analysed as factors affecting incidence of shoulder dystocia and subsequent neonatal injury.
Results Among women who met study criteria, 252 (2.4%) experienced a shoulder dystocia. Women of black ethnic background (African and Afro-Carribean) had the highest percetage of shoulder dystocia (43.8%), compared with White background (39.5%) and the lowest was amongst women of Asian background (16.6%). Additionally, in the setting of a shoulder dystocia, a higher risk of brachial plexus injury was observed in neonates delivered by women of Black background taking in to account confounding factors such as birth weight, gestational diabetes and previous shoulder dystocia.
Conclusions Overall women of black background have an increased risk of shoulder dystocia and their neonates are more likely to experience birth injury subsequently. Induction of labour and infant birth weight greater than 4000g have traditionally been identified as significant independent predictors of shoulder dystocia; however ethnicity should be taken into account when considering caesarean section as prophylaxis against shoulder dystocia and neonatal investigations for possible brachial plexus injuries post birth.