A Cochrane review included 56 trials involving a total 7 738 women. The risk of not achieving vaginal delivery within 24 hours was decreased with intracervical prostaglandins E2 (PGE2) compared to placebo (RR 0.61; 95% CI 0.47 to 0.79, 4 trials, n=198) but increased with intracervical PGE2 compared to vaginal PGE2 (RR 1.26; 95% CI 1.12 to 1.41, 11 trials, n=2 200). The risk of caesarean section was non-significantly reduced with intracervical PGE2 compared with placebo/no treatment (RR 0.88; 95% CI 0.77 to 1.00, 27 trials, n=3 734), and not altered with intracervical vs vaginal PGE2 (RR 1.07; 95% CI 0.93 to 1.22, 28 trials, n=3 781). The risk of hyperstimulation with fetal heart rate changes was not significantly increased with intracervical PGE2 vs placebo/no treatment (RR 1.21; 95% CI 0.72 to 2.05, 12 trials, n=2 296) or with intracervical vs vaginal PGE2 (RR 0.76; 95% CI 0.39 to 1.49, 13 trials, n=1 428). Intracervical dose was lower than vaginal dose.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment).