Inappropriate gestational weight gain (GWG), either above or below the recommended values, has been associated with an increased risk of adverse obstetric outcomes. To evaluate the risks of GWG for foetal acidosis according to pre-pregnancy body mass index (BMI) and mode of delivery, we analysed women with singleton pregnancies between 2011 and 2014 in the Japan Environment and Children’s Study. Participants (n = 71,799) were categorised according to pre-pregnancy BMI. GWG was categorised into insufficient, appropriate, or excessive. Foetal acidosis was defined as umbilical artery pH (UmA-pH) < 7.20 or < 7.10. Multiple logistic regressions were performed for each BMI category to identify the risks of GWG for foetal acidosis, accounting for the mode of delivery. Excessive GWG was significantly associated with increased foetal acidosis in overweight women and in women whose pre-pregnancy BMI was 23.0–25.0 kg/m² especially in those with vaginal deliveries. Conversely, excessive GWG was not significantly associated with increased foetal acidosis in obese women and in women whose pre-pregnancy BMI was ≥ 25.0 kg/m².

不适当的妊娠体重增加 (GWG)，无论是高于还是低于推荐值，都与不良产科结果的风险增加有关。为了根据孕前体重指数 (BMI) 和分娩方式评估 GWG 对胎儿酸中毒的风险，我们在日本环境与儿童研究中分析了 2011 年至 2014 年间单胎妊娠的女性。参与者 (n = 71,799) 根据孕前 BMI 进行分类。GWG 分为不足、适当或过多。胎儿酸中毒定义为脐动脉 pH (UmA-pH) < 7.20 或 < 7.10。对每个 BMI 类别进行多重逻辑回归，以确定 GWG 对胎儿酸中毒的风险，考虑分娩方式。²尤其是阴道分娩者。相反，在肥胖女性和孕前 BMI ≥ 25.0 kg/m ^{2 的}女性中，过多的 GWG 与胎儿酸中毒的增加没有显着相关性。