Objective: To evaluate the association between maternal pre-pregnancy body mass index and fetal acidosis while accounting for the mode of delivery. Design: Prospective cohort study Setting: Japan Population: Participants from the Japan Environment and Children’s Study with singleton pregnancies after 22 weeks of gestation who gave birth during 2011–2014 Methods: Participants were categorized into five groups according to pre-pregnancy body mass index (BMI) (kg/m2): G1 (BMI<18.5), G2 (18.5 to <20.0), G3 (20.0 to <23.0), G4 (23.0 to <25.0), and G5 (≥25.0). Multiple logistic regression analysis evaluated the effect of maternal pre-pregnancy BMI on fetal acidosis while accounting for the mode of delivery. Main outcome measures: Fetal acidosis was defined as umbilical artery pH (UmA-pH) <7.2 or <7.1. Results: We analyzed 71,799 participants. Adjusted odds ratios (aORs) of UmA-pH <7.2 using G3 as the reference group were 1.17 (95% confidence interval [CI], 1.06–1.30) in G5 and 0.89 (95% CI, 0.82–0.97) in G2. After stratification, aORs of UmA-pH <7.2 were 1.12 (95% CI, 1.08–1.35) in G5 and 0.90 (95% CI, 0.83–0.98) in G2, and the aOR of UmA-pH <7.1 was 0.80 (95% CI, 0.65–0.98) in G2 using G3 as the reference group for vaginal delivery. No association existed between pre-pregnancy BMI and fetal acidosis for delivery via cesarean section. Conclusions: In Japanese women, pre-pregnancy BMI ≥25.0 kg/m2 significantly increased the likelihood of fetal acidosis in newborns delivered vaginally.

Objective: To investigate the correlation of prepregnancy dietary inflammatory index (DII) with obstetric outcomes in women with endometriosis. Design: Prospective cohort study Setting: Japan Population: We identified 88,398 Japanese women (n=85,149 without endometriosis and n=3,249 with endometriosis) who were recruited in the Japan Environment and Children’s study (JECS) between January 2011 and March 2014. Methods: Participants were categorised according to DII quintiles (Q1 and Q5 were the most pro-inflammatory and most anti-inflammatory groups, respectively) and stratified according to the presence or absence of endometriosis. Women with endometriosis were further categorised based on conceptions after assisted reproductive technology. Main outcomes were preterm birth (PTB) and low birth weight (LBW) infant. A multiple logistic regression model was used to estimate the effect of anti-inflammatory diet on PTB before 37 or 34 weeks and LBW <2500 g or 1500 g. Results: In women with endometriosis without ART, Q5 significantly decreased the risk of PTB before <34 weeks (aOR 0.25, 95% CI 0.07–0.83) and LBW <1500 g (aOR 0.07, 95% CI 0.01–0.60). Conclusions: This study suggested a distinctive effect of anti-inflammatory diet on more severe obstetrics outcomes, specifically PTB before 34 weeks and LBW <1500 g, among women with endometriosis. Moreover, preconception lifestyle may improve perinatal mortality and morbidity among women with endometriosis. Funding: None