Title: Randomized study on two dinoprostone administration routes for cervical priming and labor induction in low-bishop pregnancy
Abstract: Dinoprostone vaginal insert was compared to dinoprostone cervical gel in few studies, enrolling patients with different Bishop scores (BS), gestational ages (GA), and treatments in controls. Present study compares vaginal insert to cervical gel in patients with low inducibility at term. Prospective, multicenter, randomized trial, with parity-based randomization. Admission criteria: single pregnancy with BS of 0-4, GA 37-41.0 weeks, intact membranes, no previous CS or bleeding or abnormal CTG at admission. Study patients (group A, 56 cases) maintained vaginal insert until labor or PROM or for 12 hours. After 12 hours, patients with BS <4 received dinoprostone vaginal gel for two administrations with 8-hour interval, patients with BS >4 underwent amniorrhexis (AMX) and oxytocin infusion. Control arm (group B, 51 patients) received two 0.5-mg dinoprostone cervical gel applications with 6-hour interval, with further management equal to that of group A. Groups (A vs B) were comparable for nulliparity (61% vs 59%), admission median BS (3 in both), GA (39.1 wks in both), induction indications, and neonatal birthweight (3201±479 vs 3163±498 grams). Second-line induction (vaginal PG or AMX or both) was required in 52% group A patients vs 49% control patients. Group A patients experienced shorter induction-to-delivery time (920±427 vs 1266±740 minutes, P<0.01, Student's t-test). Groups A ad B showed similar incidence of abnormal CTG during labor (15.7% vs 10.4%, P = 0.63, chi-square), hypercynetic labor (29.4% vs 27.1%), CS (21.4% vs 21.6%), CS for fetal distress (12.5% vs 11.8%), and umbilical artery pH <7.10 (4.9% vs 2.5%, P = 1.0, Fisher's exact test). Both methods require 50% of second-line induction procedures, but vaginal insert leads to delivery with a shorter latency time. Even if both methods seem to be equally safe for the mother and the newborn, larger studies should investigate neonatal outcome.