Clomifene citrate or low-dose FSH for the first-line treatment of infertile women with anovulation associated with polycystic ovary syndrome: a prospective randomized multinational study

background: Clomifene citrate (CC) is accepted as the first-line method for ovulation induction (OI) in patients with polycystic ovary syndrome (PCOS) associated with infertility owing to anovulation. Low-dose FSH has been reserved for women failing to conceive with CC. In this RCT, we tested the hypothesis that pregnancy rate (PR) and live birth rates (LBR) are higher after OI with low-dose FSH than with CC as first-line treatment. methods: Infertile women (,40 years old) with PCOS-related anovulation, without prior OI treatment, attending 10 centres in Europe/South America were randomized to OI with either CC (50–150 mg/day for 5 days) or FSH (starting dose 50 IU) for up to three treatment cycles. The primary outcome was clinical PR. results: Patients (n ¼ 302) were randomized to OI with FSH (n ¼ 132 women; 288 cycles) or CC (n ¼ 123; 310 cycles). Per protocol analysis revealed that reproductive outcome was superior after OI with FSH than with CC with respect to PR per first cycle [30 versus 14.6%, respectively, 95% confidence interval (CI) 5.3–25.8, P ¼ 0.003], PR per woman, (58 versus 44% of women, 95% CI 1.5–25.8, P ¼ 0.03), LBR per woman (52 versus 39%, 95% CI 0.4–24.6, P ¼ 0.04), cumulative PR (52.1 versus 41.2%, P ¼ 0.021) and cumulative LBR (47.4 versus 36.9%, P ¼ 0.031), within three cycles of OI.