Seven RCTs (713 couples) were included.
All 7 trials were considered to be of a reasonable methodological standard. Two studies clearly described the method used for random allocation. None of the included trials were blinded and none performed a power calculation.
CC and IUI versus NC and TI: 3 RCTs (141 couples undergoing 862 cycles) were identified. A statistically significant improvement in CPR was found with CC plus IUI compared with NC combined with TI (OR 4.6, 95% CI: 1.9, 11.3); no statistical heterogeneity was found.
CC and IUI versus NC and IUI: 2 RCTs (96 couples undergoing 162 cycles) were identified. No statistically significant difference in CPR was demonstrated between the treatment groups (OR 2.4, 95% CI: 0.8, 7.3); no statistical heterogeneity was found.
CC and IUI versus CC and TI: 2 RCTs (197 couples undergoing 138 cycles) were identified. A non-statistically significantly higher CPR was found for treatment with CC and IUI compared with CC and TI (OR 0.9, 95% CI: 0.3, 3.0); statistically significant heterogeneity was found (P=0.02).
CC and IUI versus Gn and IUI: 3 RCTs (279 couples undergoing 348 cycles) were identified. A statistically significantly higher CPR was demonstrated with Gn combined with IUI in comparison with CC and IUI (OR 2.9, 95% CI: 1.3, 6.2); no statistical heterogeneity was found.
CC and IUI versus Gn and in vitro fertilisation: no RCTs were identified.