(1176) The association of sodium intake with the development of hypertensive disorders of pregnancy

To assess the association between daily sodium intake and risk of hypertensive disorders of pregnancy.

Study Design:

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.

Results:

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).

Conclusion:

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.