Impact of Gestational Weight Gain on Trial of Labor After Cesarean Success [38O

Abstract

INTRODUCTION: Maternal obesity has been associated with decreased success of a trial of labor after cesarean delivery (TOLAC). We aimed to investigate the BMI and gestational weight changes on TOLAC success in a modern cohort. METHODS: This is a retrospective cohort study of women attempting TOLAC at a single institution from May 2007 to April 2016. Exclusion criteria included age less than 19 years, fetal demise, lethal fetal anomalies, or incomplete medical records. Clinical data collected included maternal demographics, comorbidities, obstetric history, obstetric complications and outcomes, and BMI prior to and throughout pregnancy. Chi squared analysis was used to detect differences between groups. RESULTS: 614 patients met inclusion criteria. The overall TOLAC success rate was 72.31% (n=444) and average BMI at delivery was 30.7. Compared to normal weight women, we found no difference in success rates among women who were obese prior to pregnancy (73.2% vs 72.1%, P=.794), became obese during pregnancy (69.8% vs 73.3%, P=.379), or were obese at the time of delivery (71.1% vs 73.6%, P=.483). Appropriate weight gain during pregnancy (within Institute of Medicine recommendations) also did not impact TOLAC success (74.1% normal vs 71.4% excess P=.483). A post-hoc power analysis showed that we were powered to detect a 12.5% difference in TOLAC success rates. CONCLUSION: In contrast with prior studies, we found no difference in TOLAC success rates with maternal obesity or excess gestational weight gain. Our findings suggest that obesity may not have a negative impact on TOLAC success as previously reported.