Twelve trials were included in the review with 2,875 participants (1,556 allocated to rFSH and 1,319 allocated to uFSH). In four trials, both IVF and ICSI were performed, in seven trials only IVF was performed, and in one trial only ICSI was performed.
The pooled OR was 1.20 (95% CI: 1.02, 1.42; P = 0.03) in favour of rFSH which was statistically significant. The risk difference represented a 3.7% (95% CI: 0.5, 6.9%) increase in clinical pregnancy rate per cycle started with rFSH, compared with uFSH. There was no significant heterogeneity of treatment effect across all trials (Breslow-Day statistic = 7.5, P = 0.94).
In the subgroup analysis of follitrophin alpha with uFSH (9 trials, 1,639 cycles, 13 comparative assessments), the OR was 1.21 (95% CI: 0.97, 1.51; P = 0.09) in favour of rFSH which was not statistically significant. The risk difference was 3.7% (95% CI: -0.5, 7.9%). There was no significant heterogeneity of treatment effect across all trials (Breslow-Day statistic = 7.3, P = 0.84).
In the subgroup analysis of follitrophin beta with uFSH (3 trials, 1,236 cycles), the OR was 1.19 (95% CI: 0.93, 1.53; P = 0.16) in favour of rFSH which was not statistically significant. The risk difference was 3.7% (95% CI: -1.5, 8.8%). There was no significant heterogeneity of treatment effect across all trials (Breslow-Day statistic = 0.20, P = 0.91).
In the analysis of the trials of IVF data, (11 trials, 2,308 cycles), the OR was 1.26 (95% CI: 1.05, 1.52; P = 0.02) in favour of rFSH which was statistically significant. The risk difference was 4.4% (95% CI: 0.9, 8.0%). There was no significant heterogeneity of treatment effect across all trials (Breslow-Day statistic = 5.0, P = 0.89).
In the analysis of the trials of ICSI data, (5 trials, 567 cycles), the OR was 1.02 (95% CI: 0.72, 1.45; P = 0.92) in favour of rFSH which was not statistically significant. The risk difference was 0.3% (95% CI: -7.4, 7.9%). There was no significant heterogeneity of treatment effect across all trials (Breslow-Day statistic = 1.4, P = 0.84).
In the logistic regression analysis, the clinical pregnancy rate was significantly higher when ICSI was performed, compared with IVF (OR 1.3, 95% CI: 1.1, 1.6). Similarly, rFSH was associated with a significantly higher clinical pregnancy rate, compared with uFSH (OR 1.2, 95% CI: 1.1, 1.5).
The pregnancy rate with the alpha preparation of rFSH was statistically significantly higher than with uFSH in IVF cycles.
The funnel plot analysis showed a symmetrical distribution of data indicating that publication bias was unlikely. No trial was designed with adequate power to test the null hypothesis of no difference in pregnancy rates between the two gonadotropin preparations.