Impact of pre-pregnancy body mass index on preeclampsia

Jing Mao ^* Hanxiang Sun Qinxin Shen ^* Chang Zou Yuanyuan Yang ^* Qiaoling Du ^*

• Shanghai First Maternity and Infant Hospital, Shanghai, China

How does pre-pregnancy body mass index (BMI) affect preeclampsia for Chinese population remains undetermined, especially lacking support from large-scale research.To figure out relation between pre-pregnancy BMI and (severe) preeclampsia among Chinese population, providing detailed description of the findings.The retrospective study enrolled a total of 75,773 pregnant women who were registered between 2016 and 2020. These participants were categorized into four groups based on their The retrospective research enrolled a total of 75,773 pregnant women registered from 2016 to 2020 and stratified these individuals into four groups, based on their levels of pre-pregnancy BMI: underweight (BMI < 18.5 kg/m² ), normal weight (BMI 18.5-<24 kg/m² ), overweight (BMI 24-<28 kg/m²), and obese (BMI ≥ 28 kg/m²). Relations between risks of preeclampsia or severe preeclampsia and pre-pregnancy BMI were further explored, with an evaluation of potential modification by maternal age.A lower risk of developing preeclampsia was observed in underweight population, with an OR of 0.604 (95%CI, 0.507-0.719). In contrast, women overweight or obese in prepregnancy period demonstrated significantly higher preeclampsia risk, with ORs of 2.211 (95%CI, 1.967-2.486) and 3.662 (95%CI, 3.026-4.431), respectively. After adjusting for confounding factors, the elevated preeclampsia risks persisted, showing ORs of 2.152(95%CI, 1.911-2.425)1.956 (95%CI, 1.736-2.204) for overweight population and 3.493(95%CI, 2.874-4.245)3.108 (95%CI, 2.559-3.774) for those obese, while risk for underweight women remained lower, with an OR of 0.609(95%CI, 0.511-0.727)0.638 (95%CI, 0.535-0.761). For severe preeclampsia, the risks were also higher in overweight and obese subjects following adjusting for confounders, demonstrating ORs of 1.652(95%CI, 1.364-2.001)1.378 (95%CI, 1.139-1.669) and 2.762(95%CI, 2.014-3.788)2. 335 (95%CI,, respectively. Underweight population exhibited lower severe preeclampsia risk as well, with an OR of 0.720(95%CI, 0.565-0.919)0.778 (95%CI, 0.609-0.993). In addition, these risks were not significantly associated with maternal age.No significant interaction between maternal age and preeclampsia or severe preeclampsia occurrence was observed.Regardless of adjustment for confounders, underweight women demonstrated lower preeclampsia risk, whereas overweight/obese population exhibited more occurrence of both preeclampsia and severe preeclampsia. These associations were not influenced by maternal age.