Uterine and fetal Doppler flow changes after misoprostol and oxytocin therapy for induction of labor in post-term pregnancies

Objectives: To compare the effect of misoprostol vs. oxytocin on blood flow in uteroplacental circulation during labor induction. Methods: Ninety-one women with indications for induction of labor were assigned to receive eith er misoprostol 50 mu g per vagina every 4 h as needed or intravenous oxytoc in by means of a randomization table generated by computer. Doppler velocim etry of umbilical, uterine and arcuate arteries was performed immediately b efore and 2-3 h after administration of misoprostol or oxytocin. Pulsatilit y index (PI), resistance index (RT) and systolic/diastolic (S/D) ratios wer e measured for these arteries. The SAS system was used to perform statistic al analysis. Results: There were no significant changes of PI, RI and S/D r atios in umbilical arteries during misoprostol and oxytocin inductions. Vag inal application of misoprostol significantly increased PI, RI and S/D rati os in arcuate arteries and S/D ratio in uterine arteries. Conclusions: Our results indicate that intravaginal misoprostol administration increases ute roplacental resistance but probably does not substantially affect placental perfusion. (C) 1999 International Federation of Gynecology and Obstetrics.