Nifedipine and platelets in preeclampsia.

In addition to its antihypertensive properties, nifedipine inhibits platelet aggregation in vitro. Because increased platelet aggregation is a feature of preeclampsia, we have investigated nifedipine in this condition. Ten women at 31 +/- 2.8 weeks gestation, with blood pressure 162 +/- 18/102 +/- 10 mmHg (despite atenolol 200 mg/day) and proteinuria 2.0 +/- 1.1 g/24 hr, were treated with nifedipine. Pregnancies were prolonged by 17 +/- 15 days (range 5 to 56). Blood pressure was controlled in eight of the ten patients, final values before delivery being 142 +/- 16/89 +/- 12 mmHg (P less than 0.02). Platelet count rose in all women from 190 +/- 80 to 261 +/- 78 X 10(9)/1 (P less than 0.001). Nifedipine appears to reverse the thrombocytopenia of pre-eclampsia, in addition to controlling the blood pressure.