Maternal pre-pregnancy body mass index and foetal acidosis in vaginal and caesarean deliveries: The Japan Environment and Children’s Study

Abstract

A high maternal body mass index (BMI) is associated with increased risks of asphyxia-related neonatal morbidity. We evaluated the association between maternal pre-pregnancy BMI and foetal acidosis while accounting for the mode of delivery. Participants from the Japan Environment and Children’s Study with singleton pregnancies after 22 weeks of gestation who gave birth during 2011–2014 were included. The participants (n = 71,799) were categorised into five groups according to the pre-pregnancy BMI: G1 (BMI < 18.5 kg/m2), G2 (18.5 to < 20.0 kg/m2), G3 (20.0 to < 23.0 kg/m2), G4 (23.0 to < 25.0 kg/m2), and G5 (≥ 25.0 kg/m2). Foetal acidosis was defined as umbilical artery pH (UmA-pH) < 7.20 or < 7.10. Multiple logistic regression analyses were used to evaluate the effect of pre-pregnancy BMI on foetal acidosis risk, accounting for the mode of delivery. In Japanese women, pre-pregnancy BMI ≥ 25.0 kg/m2 significantly increased the likelihood of foetal acidosis in newborns delivered vaginally. We found no association between pre-pregnancy BMI and foetal acidosis in newborns delivered via caesarean section. Counselling for body weight control before pregnancy and adequate management and selection of the mode of delivery in pregnant women with a high BMI who are in labour may be essential to avoid foetal acidosis.

Effect of gestational weight gain on placental weight: A single tertiary referral center study of Japanese women

“…Recently, some studies validated the appropriate gestational weight gain for different pre-pregnancy BMI categories based on the risk of adverse obstetric outcomes in Japan. 14,15,17,18 In the present study, we referred to pre-pregnancy BMI categories and recommended weight gain during pregnancy based on these studies (Table 2), because both participants of previous studies and those of the present study comprised only Japanese individuals, and we used validated placental weight accounting for gestational age and sex of newborns using a Japanese sample. 16 Overweight and obesity are often the consequence of an accumulation of unhealthy lifestyles.…”

“…The participants were categorized into five groups according to their BMI before pregnancy: group 1 (G1), <18.5 kg/m 2 ; group 2 (G2), 18.5 to <20.0 kg/m 2 ; group 3 (G3), 20.0 to <23.0 kg/m 2 ; group 4 (G4), 23.0 to <25.0 kg/m 2 ; and group 5 (G5), > 25.0 kg/m 2 . 14,17,18 Gestational weight gain was calculated by subtracting the weight before pregnancy (kg) from the weight immediately before delivery (kg). Thus, for the subsequent analysis of pre-pregnancy BMI on the z-score of placental weight, gestational weight gain was categorized into "insufficient," "appropriate," or "excessive," based on the pre-pregnancy BMI according to criteria described by previous Japanese epidemiological study (Table 1).…”

“…Thus, for the subsequent analysis of pre-pregnancy BMI on the z-score of placental weight, gestational weight gain was categorized into "insufficient," "appropriate," or "excessive," based on the pre-pregnancy BMI according to criteria described by previous Japanese epidemiological study (Table 1). 14,15,17,18 Outcomes Birthweight and placental weight were measured by a midwife soon after delivery. The z-scores of birth weight were calculated using the "New Japanese Neonatal Anthropometric Charts".…”

Urinary 8-hydroxy-2′-deoxyguanosine levels and small-for-gestational age infants: a prospective cohort study from the Japan Environment and Children’s Study

“… 26 BMI before pregnancy was categorised into three groups (<18.5 kg/m 2 , 18.5–24.9 kg/m 2 and ≥25.0 kg/m 2 ). 27 Parity was categorised into two groups (nulliparous and multiparous).…”

Association between maternal ritodrine hydrochloride administration during pregnancy and childhood wheezing up to three years of age: The Japan environment and children's study

“…Maternal participants were divided into three age groups when reporting childbirth details (nearly equal to the age at childbirth): <20, 20–34, and ≥35 years 30,31 . Maternal BMI before pregnancy was categorized 32 as <18.5, 18.5–24.9, and ≥25.0 kg/m 2 . Parity was categorized as nulliparous and multiparous.…”