A total of 23 studies were included (n=7,493). A total of 3,030 participants had conservative management and delayed induction; 1,735 had vaginal prostaglandins, 2,722 had immediate oxytocin induction.
The ORs and 95% CIs derived from the random-effects (DerSimonian) analysis are given below by treatment comparison and by outcome:
Immediate oxytocin versus conservative management: chorioamionitis OR 0.91 (95% CI: 0.51,1.62); endometritis OR 0.78 (95%:0.50,1.21; Caesarean birth OR 1.24 (95%CI: 0.89, 1.73), neonatal infection OR 0.73 (95% CI: 0.47, 1.13).
Prostaglandins versus conservative management: chorioamnionitis OR 0.68 (95% CI: 0.51,0.91); endometritis OR 0.81 (95%:0.53,1.23; Caesarean birth OR 0.95 (95%CI: 0.76,,1.20), neonatal infection OR 1.06 (95% CI: 0.67, 1.66).
Prostaglandins versus oxytocin: chorioamnionitis OR 1.55 (95% CI: 1.09,2.21); endometritis OR 0.78 (95%:0.23,2.62; Caesarean birth OR 0.67 (95%CI: 0.34,,1.29), neonatal infection OR 1.50 (95% CI: 0.91, 2.45).
Therefore vaginal prostaglandins resulted in more chorioamionitis than immediate oxytocin, but less than conservative management. These results were consistent with those obtained from the fixed-effect analysis, with the exception of the incidences of chorioamnionitis and endometritis in the immediate oxytocin/conservative management comparison (Mantel-Haenszel pooled ORs, respectively, 0.67, 95% CI: 0.52, 0.85 and 0.71, 95% CI: 0.51, 0.99).
There was significant heterogeneity among the trials pooled for the chorioamionitis outcome (chi-squared (8) =23.99, tau=0.39. p<0.01). When only the 'true' RCTs were included in the analysis, the DerSimonian pooled ORs found a significantly lower incidence of chorioamionitis with immediate oxytocin compared with conservative management and with vaginal prostaglandins compared with conservative management (ORs, respectively, 0.43, 95% CI: 0.31, 0.60 and 0.68, 95% CI:0.51, 0.91). Subgroup analyses found that in studies with no digital analyses found one significant treatment difference but this was based on a small number of patients. Other subgroup analyses did not reveal any further treatment differences.