Pre-pregnancy fat intake in relation to hypertensive disorders of pregnancy

Abstract

Many studies have linked intakes of fat and of specific fatty acids during pregnancy with preeclampsia; however, information on the association of intake before pregnancy with hypertensive disorders of pregnancy (HDP) is scant. We evaluated the associations of intakes of major and specific types of fat before pregnancy with the risks of HDP, including preeclampsia and gestational hypertension (GHTN). We followed 11,535 women without chronic disease participating in the Nurses' Health Study II from 1991 and 2009. Pre-pregnancy dietary fat was assessed by an FFQ. Intakes of total fat, saturated fat, trans fatty acid (TFA), MUFAs, PUFAs, and fat subtypes (omega-3 and omega-6) were categorized into quintiles of intake. HDP were self-reported. The RRs (95% CIs) of HDP were estimated by log-binomial generalized estimating equation regression models, with an exchangeable correlation matrix to account for repeated pregnancies while adjusting for potential confounders. During 19 years of follow-up, there were 495 cases of preeclampsia (2.9%) and 561 (3.3%) cases of GHTN in 16,892 singleton pregnancies. The mean age at pregnancy was 34.6 years (SD, 3.9 years). Among major fat types, only pre-pregnancy TFA was related to a higher risk of HDP (RR, 1.32; 95% CI: 1.05-1.66), and only for preeclampsia (RR, 1.50; 95% CI: 1.07-2.10) but not for GHTN (RR, 1.21; 95% CI: 0.87-1.70). Among specific types of PUFAs, intake of arachidonic acid was positively related with GHTN (RR, 1.43; 95% CI: 1.00-2.04) but not preeclampsia (RR, 1.08; 95% CI: 0.75-1.57). In analyses restricted to pregnancies 1 year after the diet assessment, women with the highest intake of long-chain omega-3 fatty acids had a 31% lower risk of HDP (95% CI: 3%-51%), which was driven by preeclampsia (RR, 0.55; 95% CI: 0.33-0.92). Pre-pregnancy intakes of total fat, saturated fat, and MUFA were unrelated to HDP, whereas TFA was positively related to HDP. These findings highlight the importance of ongoing efforts to eliminate TFA from the global food supply.