Eskew EM, et al. - Via a systematic review and meta-analysis, researchers sought to compare the clinical efficacy, as determined by positive pregnancy test, of letrozole and clomiphene citrate for ovarian stimulation in patients with unexplained infertility. Including 8 RCTs comprising 2,647 patients with unexplained infertility, they identified that the studies of ovarian stimulation in women with unexplained infertility were heterogeneous but display no difference in clinical outcomes between letrozole and clomiphene citrate.