The correlation analysis of weight and blood pressure during the pregnancy and its influencing factors: a retrospective study

This study aimed to evaluate the correlation between maternal weight and blood pressure during pregnancy and determine the magnitude of blood pressure changes per kilogram of weight gained. Additionally, we investigated whether this relationship differs among women with gestational diabetes mellitus (GDM) and various categories of hypertensive disorders of pregnancy. This retrospective cohort study analyzed 4,051 pregnancies delivered at Tianjin Medical University Second Hospital between January 2019 and December 2020. We performed covariance analysis controlling for maternal age, gestational weight gain, and neonatal birthweight, followed by simple linear regression to quantify blood pressure changes per kilogram of maternal weight. Subgroup analyses examined these relationships in women with and without GDM, chronic hypertension (CH), gestational hypertension (GH), and normotensive pregnancies. A moderate correlation existed between maternal weight and both systolic (r = 0.427, p < 0.001) and diastolic (r = 0.397, p < 0.001) blood pressure. Each kilogram increase in maternal weight was associated with a 0.47mmHg increase in systolic and 0.325mmHg increase in diastolic blood pressure. These correlations were comparable between women with and without GDM (r = 0.411 vs. r = 0.406 for systolic; r = 0.392 vs. r = 0.372 for diastolic blood pressure). However, correlations were notably attenuated in women with chronic hypertension (r = 0.202 for systolic; r = 0.095 for diastolic blood pressure) compared to those with gestational hypertension or normotensive pregnancies. Maternal weight demonstrates a moderate correlation with blood pressure during pregnancy, with greater impact on systolic than diastolic parameters. This relationship remains consistent regardless of gestational diabetes status but is significantly diminished in women with chronic hypertension. Appropriate weight management may contribute to blood pressure control during pregnancy, particularly for women without pre-existing hypertensive disease.