The association of sodium intake with the development of hypertensive disorders of pregnancy

Abstract

To assess the association between daily sodium intake and risk of hypertensive disorders of pregnancy. This was a secondary analysis of the prospective Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-To-Be study. In this analysis, we included those with non-anomalous, singleton pregnancies who completed food frequency questionnaires in which they recorded their sodium intake in the 3 months prior to pregnancy. Individuals who did not progress beyond 20 weeks’ gestation were excluded. Sodium intake was categorized as low (< 2g per day), medium (2g to < 3g per day), or high (≥ 3g per day). The primary outcome was development of a new-onset hypertensive disorder of pregnancy (HDP), including antenatal gestational hypertension, preeclampsia, HELLP, and superimposed preeclampsia. Other maternal and neonatal outcomes also were assessed. Kruskal-Wallis and Chi square tests were used to compare baseline characteristics. Adjusted incidence risk ratios (aIRR) with 95% confidence intervals (CIs) were estimated using Poisson regression to control for confounders. Among 7927 individuals eligible for this analysis, 2,482 (31%) reported low sodium intake, 2,978 (38%) medium sodium intake, and 2,467 (31%) high sodium intake. Baseline characteristics, including age, BMI, self-reported race and ethnicity, and tobacco use differed significantly between groups (all p< 0.01, Table 1). The risk of developing HDP was similar among groups (medium vs. low aIRR 1.03, 95% CI 0.88-1.22; high vs. low aIRR 1.13, CI 0.96-1.34). There were no differences in other adverse maternal or neonatal outcomes by sodium intake (Table 2). There was no association between sodium intake and risk of HDP. This may reflect a difference in the pathophysiology underlying pregnancy and non-pregnancy related hypertensive disorders.View Large Image Figure ViewerDownload Hi-res image Download (PPT)