Association of maternal weight gain in early pregnancy with congenital heart disease in offspring: a China birth cohort study

Abstract

Objectives Little study has reported the association of maternal weight gain in early pregnancy with fetal congenital heart disease (CHD). We aimed to explore the potential relationship based on a China birth cohort while adjusting by multiple factors.Design Cohort study.Setting China birth cohort study conducted from 2017 to 2021.Participants The study finally included 114 672 singleton pregnancies in the 6–14 weeks of gestation, without missing data or outliers, loss to follow-up or abnormal conditions other than CHD. The proportion of CHD was 0.65% (749 cases).Primary and secondary outcome measures Association between maternal pre-pregnancy weight gain and CHD in the offspring were analysed by multivariate logistic regression, with the unadjusted, minimally adjusted and maximally adjusted methods, respectively.Results The first-trimester weight gain showed similar discrimination of fetal CHD to that period of maternal body mass index (BMI) change (DeLong tests: p=0.091). Compared with weight gain in the lowest quartile (the weight gain less than 0.0 kg), the highest quartile (over 2.0 kg) was associated with a higher risk of fetal CHD in unadjusted (OR 1.36, 95% CI: 1.08 to 1.72), minimally adjusted (adjusted OR (aOR) 1.29, 95% CI: 1.02 to 1.62) and maximally adjusted (aOR 1.29, 95% CI: 1.02 to 1.63) models. The association remains robust in pregnant women with morning sickness, normal pre-pregnancy BMI, moderate physical activity, college/university level, natural conception or with folic acid (FA) and/or multivitamin supplementation.Conclusions and relevance Although the association of maternal pre-pregnancy weight gain on fetal CHD is weak, the excessive weight gain may be a potential predictor of CHD in the offspring, especially in those with morning sickness and other conditions that are routine in the cohort, such as normal pre-pregnancy BMI, moderate physical activity, college/university level, natural conception or with FA and/or multivitamin supplementation.