Gonadotrophins versus clomifene citrate with or without intrauterine insemination in women with normogonadotropic anovulation and clomifene failure (M-OVIN): a randomised, two-by-two factorial trial.

Background: In many countries, clomifene citrate is the treatment of first choice in women with normogonadotropic anovulation (ie, absent or irregular ovulation). If these women ovulate but do not conceive after several cycles with clomifene citrate, medication is usually switched to gonadotrophins, with or without intrauterine insemination. We aimed to assess whether switching to gonadotrophins is more effective than continuing clomifene citrate, and whether intrauterine insemination is more effective than intercourse.