[Sodium concentration and pre-eclampsia: is salt restriction of value?]

The significance of sodium metabolism with respect to preeclampsia is discussed in the literature with a wide range of diverging opinions. The presented work analyses the influence of a low salt diet on the symptoms of preeclampsia and the consequences for the newborn.

160 patients with preeclampsia between 1989 and 1993 were retrospectively studied. Serum sodium values (at hospital admission, lowest prepartal level, immediate and 3-8 days postpartum) were compared with the corresponding gestosis symptoms.

The mean sodium serum concentration at admission was 135.6 mmol/l (lower norm: 136 mmol/l). This was significantly different from the mean lowest prepartal value of 134.9 mmol/l (p < 0.0001). Postpartum the mean fell again significantly to 134.0 mmol/l (p < 0.0001). None of the parameters for gestosis symptoms, which were investigated (diastolic blood pressure, edema, proteinuria, serum protein levels and hyperreflexia) showed any statistically significant association with the serum sodium concentration. Five patients had very low serum natrium values, 130 mmol/l, either at admission or during hospitalisation. Three of the five infants of these patients had hyponatremia; two needed sodium supplementation.

There seems to be no reason supporting a low salt diet as therapy for preeclampsia, since it does not affect the symptoms and might lead to hyponatremia in the newborn.