Dietary Sodium Restriction Does not Prevent Gestational Hypertension: A Dutch Two-Center Randomized Trial

Abstract

Objective: To study the prophylactic effect of a sodium-restricted diet (20 mmol/day) on the incidence of gestational hypertension. Methods: Two hundred seventy healthy nulliparous pregnant women participated in a Dutch longitudinal two-center randomized intervention study on the effects of a sodium-restricted diet containing 20 mmol of sodium/day. The diet was used between week 14 of pregnancy and delivery. The control group received no dietary restrictions. Main Outcome Measures: The effects of the diet on the incidence of gestational hypertension; systolic, diastolic, and mean arterial blood pressures; birth weight; maternal weight gain; and duration of pregnancy were studied. Results: The incidence of gestational hypertension was 12.9% in the control group and 13.6% in the low-sodium group (weighted relative risk. 1.04. 95% confidence interval 0.55–1.99). There were no significant differences between the two groups regarding systolic, diastolic, and mean arterial blood pressures, birth weight, and duration of pregnancy. Maternal weight gain in the low-sodium group was significantly lower than in the control group; respectively, 8.8 (-3.6, 23.7) kg and 11.0 (-1.3, 20.8) kg [median (minimum, maximum)]. Conclusions: A low-sodium diet does not seem to reduce the incidence of gestational hypertension.