A comparative study of uterine activity and fetal heart rate pattern in labor induced with oral prostaglandin E2 or oxytocin.

Abstract

Labor was induced for medical reasons at or near term in altogether 200 patients. The women were randomly assigned to low amniotomy and either oral PGE2 or intravenous infusion of oxytocin. The initial PGE2 dose was 0.5 mg, followed by 1.0 mg every hour for up to 24 hours. Oxytocin was given as an intravenous pump infusion, starting with 5 mIU/min and rising stepwise to 20 mIU/min. Uterine contractility and fetal heart rate (FHR) were recorded by cardiotocography in 61 women receiving oxytocin and in 63 given prostaglandin E2. A detailed analysis of the contractility pattern was performed in 16 women, eight from each group. Labor was established slightly earlier in the oxytocin group than in the prostaglandin group of patients. When in labor, frequency and amplitude of contractions as well as uterine contractility were the same in both treatment groups. The frequency of atypical contractility patterns was higher in labor induced with PGE2 than with oxytocin. One period of hypertonus was observed in one patient treated with PGE2 but it was not associated with alterations in FHR and disappeared without additional therapy. Both mild and more severe variations in FHR occurred but were equally common on both treatment groups. There was no perinatal mortality among the newborns and the Apgar score 5 minutes after delivery was 8 or more.