Body weight and pregnancy

Maternal Weight Gain in Early Pregnancy with Healthy Live Offspring: Based on the China Birth Cohort Study

BACKGROUND

Research on maternal weight gain in early pregnancy with healthy live offspring is lacking for Chinese women. Based on the China birth cohort study (CBCS), we aimed to explore maternal weight gain in different groups.

METHODS

Singleton pregnancies of 6 + 0~13 + 6 weeks of gestation from the CBCS were considered, not including missing data or outliers, those lost at follow-up, or those with non-typical conditions of the offspring. Maternal first-trimester weight and body mass index (BMI) gain was considered as the early pregnancy weight minus the pre-pregnancy weight. Using Pearson's or Spearman's correlation and linear regression models to explore the relationship between maternal weight and BMI gain and gestational age (GA), stratified and sensitivity analyses were carried out to identify the study's robustness.

RESULTS

There were 25,292 singleton pregnancies with healthy live offspring who were ultimately enrolled, and there was a linear correlation between GA and maternal weight gain (=0.55 + 0.05 × GA (weeks), p < 0.001, r2 = 0.002) and BMI change (=0.21 + 0.02 × GA (weeks), p < 0.001, r2 = 0.002). The association remained robust in the stratified and sensitivity analyses of the subgroups.

CONCLUSIONS

Although the association between GA and maternal pre-pregnancy weight and BMI gain is weak, a slight correlation was shown, especially in pregnant women with a typical or low pre-pregnancy BMI, Han ethnicity, moderate levels of physical activity, natural conception, and folic acid (FA) and/or multivitamin supplementation.

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

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.