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OBJECTIVE To compare the risks of adverse perinatal outcomes by BMI categories in healthy pregnant individuals delivered by term elective repeat cesarean (ERCD) in order to describe an optimal timing of delivery in otherwise healthy patients at the highest-risk BMI threshold. STUDY DESIGN A secondary analysis of a prospective cohort of pregnant individuals undergoing ERCD at 19 centers in the Maternal Fetal Medicine Units Network from 1999-2002. Non-anomalous singletons, undergoing pre-labor ERCD at term were included. The primary outcome was composite neonatal morbidity; secondary outcomes included composite maternal morbidity and individual components of the composites. Patients were stratified by BMI classes and in order to identify a BMI threshold for which morbidity was highest. Outcomes were then examined by completed week's gestation, between BMI classes. Multivariable logistic regression was used to calculate adjusted ORs and 95% CIs. RESULTS 12,755 patients were included in analysis. Patient's with BMI ≥40 had highest rates of newborn sepsis, neonatal ICU admissions, and wound complications. While a weight-related response was observed between BMI class and neonatal composite morbidity (p<0.001), only those with BMI ≥40 had significantly higher odds of composite neonatal morbidity (aOR 1.4, 95% CI: 1.0-1.8). In analyses of patients with BMI ≥40 (n=1848), there was no difference in the incidence of composite neonatal or maternal morbidity across weeks' gestation at delivery; however, as gestational age approached 39-40 weeks, rates of adverse neonatal outcomes decreased, only to increase again at 41 weeks gestation. Of note, the odds of the primary neonatal composite were highest at 38 weeks compared to 39 weeks (aOR 1.5, 95% CI: 1.1-2.0). CONCLUSION Neonatal morbidity is significantly higher in pregnant individuals with BMI ≥40 delivering by ERCD. Despite this increased perinatal morbidity, delivery prior to 39 and after 41 weeks in these patients is associated with increased neonatal risks.