Purpose: The purpose of this study was to identify participant characteristics in the Kumamoto University Regional Center of the Japan Environment and Children's Study (K-JECS) and to investigate the association of pregnancy outcomes with pregestational maternal body mass index (BMI) and maternal weight gain during pregnancy (MWG).
Methods: The subjects were women with singleton birth, who had been recruited by the K-JECS, and were registered in the data systems for the first and second questionnaires and transcripts of medical records. The subjects were categorized by BMI with further classification by MWG. The chi-squared test and one-way analysis of variance were performed to determine the correlations of BMI and MWG with perinatal outcomes. Logistic regression analysis was performed to examine perinatal outcome risks.
Results: The subject characteristics were similar to the trends observed in the Japanese general population. The odds ratio for natural delivery was low in the overweight groups (OW) and normal weight groups (NW) with excessive weight gain. On the other hand, the risk of cesarean section was high in the OW, and risk of induced or accelerated delivery was high in the NW with excessive weight gain. The risks of preterm birth and LBW were high in the insufficient weight gain groups regardless of BMI. The risks of pregnancy-induced hypertension and gestational diabetes were high in the OW.
Keywords: Japan Environment and Children’s Study; maternal weight gain during pregnancy; pregestational maternal body mass index; pregnancy outcomes.