LOW-SODIUM DIET AND PREGNANCY-INDUCED HYPERTENSION - A MULTICENTER RANDOMIZED CONTROLLED TRIAL

Objective To examine the effectiveness of the standard policy in the N etherlands to prescribe a sodium restricted diet to prevent or to trea t mild pregnancy-induced hypertension. Design Multi-centre randomised controlled trial between April 1992 and April 1994. Setting Seven prac tices of independent midwives and one university hospital. Participant s The experimental group comprised 184 women given a low sodium diet ( less than or equal to 50 mmol sodium/day) and a control group of 177 w omen given a normal diet. Eligible women for inclusion had had a rise of blood pressure, or excessive weight gain or oedema during the anten atal period. The 361 women in the trial were recruited from 2020 nulli parae, of whom 1512 (75%) gave informed consent at the beginning of th eir pregnancy to participate in the study. Main outcome measures The d ifference between highest diastolic blood pressure after randomisation and diastolic blood pressure at the moment of randomisation; referral and admission to hospital for hypertension. Results There was no diff erence in increase of diastolic blood pressure after randomisation, th e percentage of referral and admission to hospital for hypertension, o r in obstetric outcome between the two groups. Urinary sodium excretio n after randomisation in the normal diet group was significantly highe r than in the low sodium group. Conclusion Prescribing a sodium-restri cted diet to prevent or to treat mild pregnancy-induced hypertension i s not effective. Therefore there is no need to introduce a salt restri cted diet in prenatal care, although increasing evidence shows that a low sodium diet prevents hypertension in non pregnant individuals.