Mid-trimester Fetal-placental Velocimetry Response to Nifedipine may Predict Early the Onset of Pre-eclampsia

Abstract

The effect of nifedipine on fetal-placental blood flow at 22-24 weeks in patients with pregnancy-induced hypertension (PIH) was evaluated. Twenty patients with PIH were submitted to the Doppler evaluation of fetal-placental perfusion at 22-24 weeks. The systo-diastolic (S/D) ratio and the pulsatility index (PI) of uterine, umbilical and middle cerebral arteries and systemic blood pressure were recorded before and 7 days after nifedipine administration (10 mg/ per os 3 times/day until delivery). Statistical analysis was performed with paired and unpaired t-test and the two-tailed Fisher exact test. Nifedipine significantly (p<0.05) decreased the mean systolic pressure in all patients (from 146 to 135 mmHg): 8 patients developed pre-eclampsia (PE) complicated by fetal growth restriction (FGR) (PE group), whilst the remaining were only affected by PIH (PIH group). The gestational age at delivery, neonatal birthweight and 1- and 5-min Apgar scores were significantly (p<0.001) lower in PE than in PIH women. Nifedipine treatment significantly changed the PI and S/D ratio (mean±SEM) of the uterine (PI from 0.66±0.01 to 0.51+0.01; S/D ratio: from 2.00±0.09 to 1.79+0.05) and umbilical (PI: from 1.55±0.04 to 1.40±0.02; S/D ratio: from 2.45±0.09 to 2.31±0.09) arteries and the middle cerebral PI (from 1.45±0.03 to 1.61±0.01) artery only in PIH, but not in PE patients. Fetal-placental blood flow changes after nifedipine may early identify patients at risk of PE.