A Cochrane review included 61 studies with a total of 12 819 subjects. Oxytocin alone compared with vaginal PGE2 (4 564 women) was associated with an increase in unsuccessful vaginal delivery within 24 hours in the two trials reporting this outcome (70% vs 21%, RR 3.33, 95% CI 1.61 to 6.89; 2 studies, n=58), but there was no difference in caesarean section rates (oxytocin 12.1% vs PGE2 10.9%, RR 1.11, 95% CI 0.94 to 1.30; 26 studies, n=4514). There was a small increase in epidurals when oxytocin alone was used (RR 1.09, 95% CI 1.01 to 1.17; 6 studies, n= 2949). Most of the studies included women with ruptured membranes, and there was some evidence that vaginal prostaglandin increased infection in mothers (chorioamnionitis oxytocin vs. PGs, RR 0.66, 95% CI 0.47 to 0.92; 4 studies, n= 2742) and babies (use of antibiotics RR 0.68, 95% CI 0.53 to 0.87; 2 studies, n=2564). These data should be interpreted cautiously as infection was not pre-specified in the original review protocol.
Oxytocin alone compared with intracervical PGE2 (1 331 women) was associated with an increase in unsuccessful vaginal delivery within 24 hours (50.4% versus 34.6%, RR 1.47, 95% CI 1.10 to 1.96; 2 studies, n=258) and an increase in caesarean sections (19.1% versus 13.7%, RR 1.37, 95% CI 1.08 to 1.74; 14 studies, n=1331).
Comment: The quality of evidence is downgraded by study quality (inadequate or unclear allocation concealment and lack of blinding).