The Impact of Maternal BMI on Adverse Perinatal Outcomes in Shoulder Dystocia [36D

Abstract

INTRODUCTION: Increasing BMI is associated with higher risk of shoulder dystocia (SD), but is it associated with other adverse perinatal outcomes (APOs) in the setting of SD? We sought to investigate this association. METHODS: This is a retrospective cohort study of singleton, non-anomalous, term vaginal deliveries complicated by SD between 2007–2011 using linked vital statistics and ICD-9 data. Neonatal outcomes included brachial plexus injury (BPI), clavicular fracture (CVF), 5-min-APGAR <7, neonatal intensive care unit admission (NICUa), and composite of severe neonatal outcomes (neonatal seizure, APGAR score ≤3, neonatal death). Maternal outcomes included postpartum hemorrhage (PPH), 3rd/4th-degree perineal lacerations (PLs), and maternal blood transfusion (MBT). Chi-square tests were used to compare rates of APOs among BMI categories. Multivariable logistic regression was used to control for diabetes status, race/ethnicity, age, education, insurance status, parity, and prenatal care. RESULTS: In a cohort of 21,489 births complicated by SD, we found statistically significant increasing rates of BPIs, CVFs, 5-min-APGAR <7, NICUa, and composite severe neonatal outcomes with rising maternal BMI. Incidence of PLs decreased significantly with increasing maternal BMI. Rates of PPH and MBT were not significantly different between groups. After controlling for confounders, there remained a statistically significant increase in odds of BPI, CVF, and NICUa (aOR 2.35, 1.59, and 1.26 respectively) and decreased odds of PLs (aOR 0.69, 95% CI 0.56–0.84) in obese women. CONCLUSION: Higher maternal BMI increases risk of complications in the setting of SD. Providers should exercise heightened awareness of the effect maternal BMI has on these potential outcomes when managing pregnancies complicated by SD.