Treatment of unexplained infertility with aromatase inhibitors or clomiphene citrate: a systematic review and meta-analysis

Treatment of unexplained infertility is empiric and different regimens or protocols have been used so far. Clomiphene can be used alone or combined with gonadotrophins. Aromatase inhibitors may offer an alternative for first-line treatment. To compare the efficacy of aromatase inhibitors versus climiphene, we conducted a systematic review and meta-analysis for randomized controlled trials comparing the above regimens to estimate live pregnancy rates in women with unexplained infertility. Trials were located through PubMed and Cochrane Library searches. Methodological quality of included trials has been assessed. Then, 2 x 2 tables were constructed, and pooled odds ratios (ORs) were calculated. Ten arms (273 patients) were included in the meta-analysis. ORs were homogeneous between studies (heterogeneity chi2 = 2.33, P = 0.676). No difference was observed for live pregnancies (pooled OR 0.87, 95% CI, 0.46-1.65, P = 0.666) for aromatase inhibitors versus clomiphene citrate; however, the definition of live pregnancy by the authors was clear only in one trial. Data regarding secondary outcomes were omitted, and methodogical quality of eligible trials did not reach high scores. Evidence from randomized data regarding the use of aromatase inhibitors is fragmented and weak. Aromatase inhibitors may have a role in the treatment of women with unexplained infertility desiring pregnancy. However, meticulous reporting and study design should be a priority in this field and large, registered, and properly designed randomized trials are essential to test whether aromatase inhibitors can be introduced as a first-line treatment in carefully selected subgroups of women with unexplained infertility.