Relationship between prepregnancy BMI and gestational weight gain(GWG) with preeclampsia: a study based on restricted cubic spline.

Objective: This study aimed to evaluate the nonlinear associations between prepregnancy body mass index(BMI), gestational weight gain(GWG), and the risk of preeclampsia(PE) using maternal and infant cohort data, thereby providing a scientific foundation for preventive strategies.

Methods: Pregnant women with regular obstetric checkups in Urumqi Youai Hospital were selected as study subjects from January 2020 to June 2024. They were divided into the PE group and the non-PE group. Baseline information and pregnancy outcomes were collected, and logistic regression analysis was employed to ascertain the impacts of diverse factors on the odds of developing PE; the restricted cubic spline was used to test the nonlinear relationship between prepregnancy BMI and GWG with PE.

Results: 13,294 pregnant women were included in the study, and 559 (4.20%) had PE.The prevalence of PE in underweight, normal-weight, overweight, and obese women was 1.72%, 2.85%, 6.60%, and 16.05%, respectively. However, after adjusting for confounders, only overweight and obesity were significantly associated with elevated PE odds. Logistic regression results showed that the OR was 1.68(95% CI:1.30-2.18) for the comparison between overweight and normal BMI groups, the OR was 3.16(95%CI:2.08-4.79) for the comparison between obesity and normal BMI groups. Restricted cubic spline showed that the association between prepregnancy BMI and the odds of PE showed an inverse L-shaped curve, with an inflection point of 21.5 kg/m²; the association between GWG and the odds of PE showed a J-shaped curve, with a GWG of 10.94-15.90 kg being at the lowest odds for the development of PE. For pregnant women with prepregnancy underweight, the odds of PE were significantly increased when their GWG exceeded 21.63 kg. Similarly, for those with prepregnancy normal weight, a significant elevation in the odds of PE was observed when their GWG surpassed 15.90 kg.

Conclusion: There is a non-linear relationship between prepregnancy BMI, GWG, and PE, and prepregnancy weight management and gestational weight monitoring are important for the prevention of PE.