Functional platelet modifications induced by oral magnesium supplementation in normotensive and hypertensive pregnancy.

Platelet functionality alterations have been correlated to the onset of hypertension in pregnancy and oral Mg++ supplementation has been clinically postulated to counteract such alterations. We, therefore tested the effect of 4 weeks oral Mg++ pyrrolidone carboxylate supplementation on platelet function. Forty-eight pregnant women were enrolled in the study at the beginning of the third trimester (30-32 weeks). Twenty women were preeclamptic, while 28 remained normotensive and served as controls. All the women received 360 mg/day magnesium pyrrolidone carboxylate for 4 weeks. DPH fluorescence, Na+/K(+)-ATPase and Ca(++)-ATPase activity, intracellular free Ca++ concentrations were determined prior and after the 4-weeks supplementation. Oral Mg++ supplementation significantly increased platelet DPH fluorescence in both normotensive and preeclamptic women. In normotensive pregnant women, it also significantly increased the activity of Na+/K(+)-ATPase, the activity of Ca(++)-ATPase and reduced the concentration of intraplatelet free Ca++. In hypertensive pregnant women, Mg supplementation increases Na+/K(+)-ATPase activity and decreases intracellular free Ca++; this, in turn, contributes to reducing the activity of Ca(++)-ATPase. Magnesium supplementation to preventing hypertension in pregnancy seems to have a consistent biochemical and clinical background.