Prepregnancy Plant-Based Diets and Risk of Hypertensive Disorders of Pregnancy [ID: 1377112

Abstract

INTRODUCTION: Plant-based diets have been associated with a lower risk of cardiovascular disease in adults. Specific evidence for their relationship with the risk of hypertensive disorders in pregnancy (HDP) is scarce. METHODS: We followed 11,535 healthy women (16,892 singleton pregnancies) participating in the Nurses' Health Study II (1999–2009). Diet was assessed every 4 years using a validated food questionnaire, from which we calculated a plant-based diet index (PBDI; a higher score indicates higher adherence). The women self-reported HDP including preeclampsia and gestational hypertension (GHTN). We estimated the relative risk (RR) of HDP and PBDI (in quintiles) with log-binomial regression using generalized estimating equations with adjustments for potential confounders while considering pregnancies from the same woman. RESULTS: The mean age of women at their first in-study pregnancy was 35 years. We identified 495 cases of preeclampsia (2.9%), and 561 cases of GHTN (3.3%). Women in the highest quintile of PBDI had a 28% lower risk of HDP compared to women in the lowest quartile (95% CI: −11%, −42%; P-trend=.007). The association was stronger for GHTN (RR 0.63 [0.47, 0.84], P-trend<.001) than for preeclampsia (RR 0.73 [0.53, 1.02], P-trend=.23). Mediation analysis suggested that body mass index self-reported between dietary assessment and pregnancy explained 39% (95% CI 14–70%) of the relation between PBDI and HDP and 46% (95% CI 12–84%) of the relation between PBDI and GHTN. CONCLUSION: Higher adherence to plant-based diets was associated with a lower risk of developing HDP. Much of the benefit appears to be related to improved weight control.