Dietary sodium restriction is used in the Netherlands in the prophylaxis of preeclampsia. To study the effects of long-term sodium restriction on the intake of other nutrients and the outcome of pregnancy, 68 healthy nulliparous pregnant women were randomly assigned to either a low-sodium diet (20 mmol/24 h) or an unrestricted diet. The diet was consumed between week 14 of gestation and delivery. The dietary intakes of energy, fat, protein, carbohydrate, sodium, potassium, and calcium were estimated with the dietary-history technique. A low-sodium diet reduced the intake of protein (by approximately 15 g/24 h), fat (by 20 g/24 h), and calcium (by 350 mg/24 h) and tended to decrease the energy intake (by approximately 0.7 MJ/24 h). The intakes of carbohydrate and potassium did not differ between the groups. The maternal weight gain was less in the low-sodium group (6.0 +/- 3.7 compared with 11.7 +/- 4.7 kg). Mean birth weight was not significantly different (3.2 +/- 0.5 compared with 3.4 +/- 0.5 kg).