Induction of labor with and without primary amniotomy. A randomized study of prostaglandin E2 tablets and intravenous oxytocin.

Abstract

A comparative study of labor induction has been performed on 471 consecutive patients. Primary amniotomy was performed in 227 cases, and 103 of these patients were stimulated, 57 patients with PGE2 tablets and 46 with oxytocin. In the remaining 124 cases labor was induced within 4 hours without medical stimulation. Primary amniotomy was omitted in 244 cases, as the head was not engaged and the cervix was unripe. After random allocation to the treatment groups 125 patients received PGE2 tablets (ProstinR), and 119 patients received oxytocin intravenously. After 2 days of stimulation without primary amniotomy, delivery was induced in 83 per cent of the patients receiving PGE2 and in 84 per cent of the patients receiving oxytocin. All patients on whom primary amniotomy had been performed were delivered on the first day. There was no difference in the success rate between PGE2 and oxytocin treatments in patients with the same Bishop score. The performance of amniotomy at the beginning of induction led to a significantly lower total dose as well as a lower maximal dose of PGE2 and oxytocin. There was no difference in the duration of active labor in patients receiving PGE2 or oxytocin. There were no differences in the incidence of fetal distress and low Apgar scores between the different groups. No serious side effects occurred. Vomiting and diarrhea in 14 patients (8 per cent) receiving PGE2 was in contrast to 3 patients with these symptoms (2 per cent) in the oxytocin group. Oral administration of PGE2 is a convenient, effective and safe alternative to oxytocin for the induction of labor; however, PGE2 was not found superior to oxytocin in cases with a low Bishop score.