Evaluation of the relationship of sodium in drinking water and toxemia of pregnancy

Salt restriction for toxemias of pregnancy is still widely used although some studies have shown that it has an adverse or no effect. Because the range of sodium levels in drinking water supplies in Houston, Texas, provides a means of comparing this relationship, hospital and outpatient records for 537 preeclampsia, eclampsia, and unspecified toxemia cases were compared with those of 537 control cases of uncomplicated pregnancy. Study and control groups were matched by age, race, obstetrical history, and month of delivery. Sodium levels were determined by relating the patient's address to a survey of sodium levels in 50 local drinking water sources. Although blood pressure during pregnancy and at discharge was significantly higher for the toxemia group, no significant relationships in the sodium value in drinking water between study and control groups were found.