Objective: To discern the optimal plan for delivery in nulliparous women with obesity at term gestation. Design: Large population-based retrospective cohort study Setting: Maternity hospitals in Ontario, Canada Population: Nulliparous women with obesity (BMI>30) with live, singleton, uncomplicated term gestations (37+0 to 41+6 weeks) between April 1st, 2012 and March 31st, 2019 Methods: Women were divided by plan for delivery (expectant management, induction of labour and no-labour caesarean section). The outcomes of interest were adverse delivery outcomes. Analyses were conducted using multivariable regression models. Analyses were stratified by each week of gestational age and by obesity class. Main Outcome Measures: The primary outcome was the Adverse Outcome Index (AOI), a binary composite of 10 maternal and neonatal adverse events. The Weighted Adverse Outcome Score (WAOS) was the secondary outcome. It provides a weighted score of each adverse event included in the AOI. Results: No-labour caesarean section reduced the risk of adverse delivery outcome by 41% (aRR 0.59, 95%CI [0.50, 0.70]) compared to expectant management at term gestation. There was no statistically significant difference in adverse birth outcomes when comparing induction of labour to expectant management (aRR 1.03, 95% CI [0.96, 1.10]). The greatest benefit to no-labour caesarean section was observed in the reduction of adverse neonatal events (aRR 0.70, 95% CI [0.57, 0.87]) particularly at 39 weeks of gestation. Conclusion: In women with obesity, no-labour caesarean section reduces adverse birth outcomes. Funding: Canadian Institute for Health Research (CIHR) (#MFM146444). Keywords: Plan for delivery, Induction of Labour, Caesarean Section, Obesity

Objective: To determine the association between placental lesions and lifetime cardiovascular disease (CVD) risk screening at 6 months postpartum following preeclampsia (PE). Design: Observational cohort study. Setting: Tertiary care centres in Ottawa and Kingston, Ontario, Canada. Population: Women diagnosed with PE who received cardiovascular screening at 6 months postpartum. Methods: Placentas from women diagnosed with PE were evaluated for histopathological lesions according to a standardised synoptic data collection form with blinding to clinical outcomes apart from gestational age at delivery. At 6 months postpartum, each participant was screened for cardiovascular risk factors and a lifetime cardiovascular risk score was calculated. A risk score >35% was deemed high risk for lifetime CVD. Main Outcome Measures: The association between placental lesions and lifetime CVD risk was assessed using odds ratios (OR, 95% confidence intervals). Results: Of the 85 participants, 53 (62.4%) screened high-risk for lifetime CVD. High-risk women had more severe lesions of maternal vascular malperfusion (MVM). MVM lesions with a severity score >2 resulted in a 3-fold increased risk of screening high risk for lifetime CVD (OR 3.10 [1.20-7.92]). MVM lesion score >2 was moderately predictive of high-risk screening (AUC 0.63 [0.51,0.75]; sensitivity: 71.8% [54.6,84.4]; specificity: 54.7% [41.5,67.3]). When clinical data was added, the model’s predictive performance improved (AUC 0.73 [0.62,0.84] sensitivity 78.4% [65.4,87.5]; specificity 51.6% [34.8,68.0]). Conclusions: PE women with MVM are more likely to screen high-risk for lifetime CVD compared to women without these lesions. Placenta pathology may provide a unique modality to identify women for postpartum cardiovascular screening.