Abstract:
OBJECTIVE: To evaluate the effect of wt gain trajectory during pregnancy on the incidence of gestational hypertension (PIH) and preeclampsia (PE). STUDY DESIGN: We conducted a nested case-control study of PIH (n = 565) and PE (n = 130) within the Pregnancy, Infection and Nutrition cohort. Cases were individually matched to controls on time at risk to a ratio of 1:3. Conditional logistic regression was used to evaluate the relationship between maternal wt gain in each trimester and risk of PIH and or PE, after adjustment for relevant covariates. The associated interactions between pre-pregnancy BMI and PIH or PE were similarly evaluated. RESULTS: The risk of PIH and PE increased in a dose-dependent manner with increasing wt gain in the 3rd trimester. However, wt gain in the 1st trimester increased the risk of PIH and PE after accounting for pre-pregnancy BMI. Increasing obesity carried increased risk of PIH and PE even at the median or less wt gain in the 1st trimester. However, an obese pre-pregnancy BMI coupled with greater than the median wt gain in the 1st trimester resulted in a multiplicative increase in risk. (Table) CONCLUSION: We found a dose dependent increase in risk of PIH and PE with increasing maternal wt gain in the third trimester. Interestingly, an effect was noted as early as the 1st trimester when BMI was considered. Therefore, in some circumstances, maternal wt gain may predict those at higher risk for PIH and PE as early as the 1st trimester.