(731) Early gestational weight gain and risk of hypertensive disorders of pregnancy.

Objective:
There is limited data on early gestational weight gain (GWG) as a modifiable risk factor to reduce the incidence of hypertensive disorders of pregnancy (HDP). We aimed to evaluate the association between GWG by 24 weeks and the development of HDP.

Study Design:
This was a retrospective cohort study of singleton pregnancies that delivered at term between 2016 and 2024 at a large health system. The primary exposure was total GWG between preconception and 24 weeks of gestation. Alternately, we also examined the rate of GWG per week. The primary outcome, HDP, was a composite of gestational hypertension and preeclampsia with and without severe features. We used logistic regression to assess the association between GWG and HDP, adjusting for maternal age, race, insurance, pre-pregnancy BMI, nulliparity, pre-existing diabetes, and chronic hypertension.

Results:
Among 29,989 eligible pregnancies, 2,446 (8.1%) individuals were diagnosed with HDP. GWG by 24 weeks was significantly associated with increased odds of HDP (aOR 1.04; 95%CI 1.03, 1.05). Figure 1 shows GWG trends across gestational age intervals stratified by prepregnancy BMI, demonstrating that those who developed HDP gained more weight at each time interval than those who did not. Increasing rate of GWG in the 1st Trimester was associated with 90% increased odds of HDP (aOR 1.90 per kg/wk of GWG; 95%CI 1.53, 2.35), and exceeding the recommended rate of GWG by the Institute of Medicine in the 2nd Trimester was associated with 19% increased odds of HDP (aOR 1.19 per kg/wk of GWG; 95%CI: 1.08–1.31). Table 1 lists the adjusted and unadjusted odds ratios for GWG at trimester-specific time points and rates of GWG in the two cohorts.

Conclusion:
Higher GWG in the first and second trimesters was linked to increased odds of HDP, highlighting  potential windows for early intervention.