Prostaglandin vaginal gel induction of labor comparing amniotomy with repeat prostaglandin gel

Michael Beckmann, Sailesh Kumar, Vicki Flenady, Ellen Harker

To compare two induction of labor protocols STUDY DESIGN: Women with live singleton pregnancies, ≥37+0 weeks, booked for PGE2 vaginal gel induction with a Modified Bishop's score <7 were eligible for inclusion. Following an evening dose of PGE2 vaginal gel, women were randomized the following morning into the amniotomy or repeat-PGE2 group. The amniotomy group underwent artificial rupture of membranes (ARM) regardless of Modified Bishop's score, and only received further PGE2 doses if ARM was not technically possible. The repeat-PGE2 group received further PGE2 (to a maximum of 3 doses) until a Modified Bishop's score ≥7, when an ARM was performed. In both groups, Syntocinon was commenced once membranes were ruptured. The primary outcome measure was time from commencement of induction until birth. Two hundred forty-five women were randomized into either the amniotomy (n=121) or repeat-PGE2 group (n=245). The time for IOL-to-birth was over 5 hours shorter in the amniotomy group (24.8h vs. 30.0h; mean difference 5.2h (95% CI -2.5,-7.8)). Fewer women in the amniotomy group remained undelivered after 24 hours (47.1% vs. 67.7%; p<0.01). However, the likelihood of an in-hours birth and the length of hospital stay was no different between the groups. There was no difference in the mode of birth or any of the secondary outcomes. After an initial dose of PGE2 vaginal gel, an amniotomy (once technically possible) is associated with a shorter IOL-to-birth time compared with using repeat doses of PGE2. Administering more PGE2 with the aim of starting contractions or making the cervix 'more favorable', appears to have no clinical advantage.