In an RCT couples with unexplained subfertility and a 30–40% probability of a spontaneous ongoing pregnancy within 12 months were randomly assigned either to intrauterine insemination with controlled ovarian hyperstimulation for 6 months or to expectant management for 6 months. In the intervention group, 42/127 (33%) women conceived and 29 (23%) pregnancies were ongoing. In the expectant management group, 40/126 (32%) women conceived and 34 (27%) pregnancies were ongoing (RR 0.85, 95% CI 0.63–1.1). There was one twin pregnancy in each study group, and one woman in the intervention group conceived triplets.
A Cochrane review included 7 trials including a total of 1159 participants with unexplained subfertility. There was no evidence that clomiphene citrate was more effective than no treatment or placebo for live birth (odds ratio (OR) 0.79, 95% CI 0.45 to 1.38) or for clinical pregnancy per woman randomised both with intrauterine insemination (IUI) (OR 2.40, 95% CI 0.70 to 8.19), without IUI (OR 1.03, 95% CI 0.64 to 1.66) and without IUI but using human chorionic gonadotropin (hCG) (OR 1.66, 95% CI 0.56 to 4.80).
Comment: The quality of evidence is downgraded by imprecise results (few patients and wide confidence intervals).