Calcium supplementation on normotensive and hypertensive pregnant women.

Normotensive and hypertensive pregnant women participated in a study to determine the effects of calcium supplementation on blood pressure. Subjects were randomly assigned to control or supplemented groups (1000 mg Ca/d). Blood pressure and serum total and ionic calcium were measured during the 20-wk supplementation period. Calcium supplementation had a significant lowering effect on diastolic blood pressure over the course of the study in the hypertensive group only. The hypertensive control subjects' mean serum ionic calcium value decreased significantly (P less than 0.05) over the course of the experiment. A significant (P less than 0.05) inverse relationship was observed between dietary calcium intake and blood pressure (r = -0.386 for systolic pressure and -0.359 for diastolic pressure).