Relationship between prenatal checkup status and low birth weight: a nationwide birth cohort-the Japan Environment and Children's Study

Purpose: We investigated the association between prenatal checkup status and low birth weight (LBW). We also sought to identify the background factors of pregnant women that influence their attendance at prenatal checkups and consider measures that might prove useful in reducing the LBW rate. Methods: Using data from a large nationwide birth cohort study, the Japan Environment and Children's Study (JECS), the sample comprised 91,916 unique mother-infant pairs with singleton live births. The outcome variable was cases of LBW, and the exposure variable was prenatal checkup status (number of visits missed). Adjusted odds ratios (AORs) with 95% confidence intervals (CIs) were calculated by logistic regression analysis. Results: AORs (95% CIs) for cases of LBW were 1.57 (1.46-1.69) for 1 missed checkup, 2.40 (1.97-2.94) for 2 missed checkups, and 2.38 (1.46-3.88) for >= 3 missed checkups. A linear trend was also observed (P <.0001). Further analysis revealed that the main risk factors for missed checkups were divorced or widowed marital status, followed by negative attitude toward pregnancy, and single marital status, whereas protective factors were being employed and better mental health in mid-late pregnancy. Conclusions: Our results suggest the importance of implementing various measures to promote regular attendance at prenatal checkups. (c) 2023 The Author(s). Published by Elsevier Inc.