Objective: To evaluate the effect of maternal sleep duration (MSD) on low birth weight infants (LBW), small for gestational age infants (SGA), and macrosomia. Design: Prospective cohort study Setting: The Japan Environment and Children’s Study (JECS) Population: Participants enrolled in JECS, with singleton pregnancies after 22 weeks, who gave birth between 2011 and 2014. Methods: Participants were categorized into five groups according to MSD during pregnancy: G1 (MSD <6.0 h), G2 (6.0–7.9 h), G3 (8.0–8.9 h), G4 (9.0–9.9 h), and G5 (10.0–12.0 h). Main outcome measures: The effect of MSD on the risk of LBW (<2,500 g and <1,500 g), SGA, and macrosomia (>4,000 g) with G2 as the reference, while adjusting for gestational excessive body weight gain (BWG). Analysis was also performed after stratification by gestational BWG. Results: We analyzed 82,171 participants. The adjusted odds ratios (aORs) of LBW <2,500 g in G4 and G5 and of SGA in G4 were 0.90 (95% confidence interval [CI], 0.83-0.99), 0.86 (95% CI, 0.76-0.99), and 0.91 (95% CI, 0.82-0.99), respectively, before adjusting for excessive gestational BWG. No significant association was observed between MSD and these outcomes after adjusting for excessive gestational BWG. Among women with appropriate gestational BWG, the aORs of LBW <2,500 g and SGA in G4 were 0.88 (95% CI, 0.80-0.97) and 0.87 (95% CI, 0.78-0.97), respectively. Conclusion: This study revealed that 9.0–9.9 h of MSD significantly decreased LBW <2,500 g and SGA in pregnant women with appropriate gestational BWG, relative to 6.0–7.9 h of MSD.
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 evaluate the incidence of adverse pregnancy outcomes (APOs) in women with uterine myomas and clarify the effect of uterine myomas on pregnancy outcomes. Design: Prospective cohort study Setting: The Japan Environment and Children’s Study (between 2011–2014) Population: Women (86,370) with singleton births after 22 weeks of gestation. Methods: Using logistic regression, the adjusted odds ratios (aORs) for APOs were calculated considering women without uterine myomas as the reference. Additionally, we used logistic regression to evaluate the effect of intrauterine infection (II) on the incidence of preterm births (PTB) and preterm premature rupture of membranes (pPROM). Main Outcome Measures: PTB (before 37 and 34 weeks), pPROM, II, and gestational hypertension (GH). Results: In women with uterine myomas, the aORs for PTB before 37 and 34 weeks, pPROM, II, and GH were 1.37 (95% confidence interval [CI], 1.22–1.54), 1.61 (95% CI, 1.27–2.05), 1.65 (95% CI, 1.33–2.04), 1.05 (95% CI, 0.75–1.46), and 1.20 (95% CI, 1.05–1.38), respectively. In women with both uterine myomas and intrauterine infection, the aORs for PTB before 37 weeks and pPROM were not significantly increased. Conclusions: Intra-pregnancy uterine myomas were associated with an increased risk of APOs. II in women with uterine myomas was not associated with PTB or pPROM. These data suggest a potential mechanical disadvantage in pregnant women with uterine myomas. Funding: Ministry of the Environment, Japan Key words: uterine myoma, preterm birth, preterm premature rupture of membrane, intrauterine infection