The effect of sublingual nifedipine on uteroplacental blood flow in hypertensive pregnancy.

The effect of nifedipine on uteroplacental blood flow was investigated in nine hypertensive women in the trimester of pregnancy and compared with the effects of a placebo in nine similar hypertensive women. An index of uteroplacental blood flow was obtained, twice before treatment and once after treatment, by measuring the increase in radioactivity in the region of the placenta with a gamma camera following an intravenous injection of indium-113m. There was no significant change in the blood flow index in either the nifedipine- or the placebo-treated groups despite a significant fall in blood pressure with nifedipine. Nifedipine lowers the blood pressure without any apparent reduction in uteroplacental blood flow.