The effect of nifedipine tocolysis on Doppler indices of the uterine and umbilical arteries.

Abstract

The aim of this study was to evaluate the effect of oral nifedipine on Doppler indices of the uterine artery (UtA) and umbilical artery (UA) before and 24 hours, 48 hours, and 1 week after tocolytic treatment. This was a prospective, self-controlled, cohort study of 65 pregnant women undergoing nifedipine tocolysis. Doppler assessment of the UtA and UA was performed before treatment and 24 hours, 48 hours, and 1 week after the initial 4 doses of 10 mg of oral nifedipine, administered at 20-minute intervals. The maintenance dosage was 20 mg of oral nifedipine administered every 6 hours for 48 hours, for a total dose of 80 mg/day. There was a decrease in the 24-hour values of the UA pulsatility index, resistance index (RI), systolic-diastolic (S:D) ratio, right UtA pulsatility index, RI, S:D ratio, and left UtA RI and S:D ratio with nifedipine therapy in comparison with the values recorded prior to nifedipine therapy. However, these differences were not statistically significant. There were no statistically significant differences between the data recorded prior to nifedipine administration and those obtained at 48 hours and 1 week after treatment. Oral nifedipine is a safe tocolytic agent with no long-term effect on fetomaternal circulation in pregnant women at risk of preterm delivery.