Couples with unexplained infertility — those in whom no significant problems are found after a fertility investigation by their doctor — struggle to find the best treatment.
Until now, fertility experts have generally agreed that the first line of therapy for such couples is a combination of clomiphene (Clomid) and intrauterine insemination, or IUI. Other experts feel that letrozole should be used instead of clomiphene since it may produce a lower risk of twin pregnancy.
Clomid vs. Letrozole trial
Researchers from the Assessment of Multiple Intrauterine Gestations from Ovarian Stimulation (AMIGOS) trial looked at this question and presented their study results at a recent annual meeting of the American Society of Reproductive Medicine (ASRM). This prospective, randomized, multicenter clinical trial involved 900 women aged 18 to 40 years. The study concluded that:
- Birth rates were lower with letrozole than with clomiphene
- More multiple births occurred with letrozole
- No difference was found in the rates of infants with birth defects or other fetal or newborn complications when comparing clomiphene to letrozole
Although both treatments were found to be safe, the higher birth rate with clomiphene should keep that as a top choice for fertility specialists treating patients with unexplained infertility.
To learn more about IUI, read a previous blog post here: Will IUI Work for Me?