Effects of letrozole alone or in combination with gonadotropins on ovulation induction and clinical pregnancy in women with polycystic ovarian syndrome: a systematic review and meta-analysis of randomized controlled trials.

Objective: To compare letrozole in combination with gonadotropins versus letrozole monotherapy in ovulation induction and clinical pregnancy among infertile women with polycystic ovarian syndrome (PCOS).

Methods: Several databases were searched for available clinical trials from inception until March 2023. We selected randomized controlled trials (RCTs) that compared sequential letrozole/gonadotropin versus letrozole alone among infertile women who met the Rotterdam criteria for PCOS. RevMan software was used to perform our meta-analysis. Our primary outcomes were ovulation and clinical pregnancy rates. Our secondary outcomes were endometrial thickness, number of mature follicles (diameter ≥ 18 mm), and incidence of miscarriage and ovarian hyperstimulation syndrome (OHSS).

Results: Six RCTs were retrieved with a total number of 723 patients. The ovulation and clinical pregnancy rates were significantly higher among the letrozole/gonadotropin group versus the letrozole monotherapy group (p < 0.001). In addition, there were significant improvements in endometrial thickness and number of mature follicles in the letrozole/gonadotropin group. There were no significant differences between the two groups regarding incidence of miscarriage and ovarian hyperstimulation syndrome.

Conclusion: Letrozole in combination with gonadotropin is superior to letrozole alone in improving ovulation induction and clinical pregnancy among PCOS patients. More trials are required to confirm our findings.