Pregnancy in Polycystic Ovary Syndrome II

Preliminary data are promising for the use of letrozole to induce ovulation in infertile women with PCOS. However the true magnitude of the effect of letrozole is difficult to discern from prior studies. Therefore we intend to determine the safety and efficacy of letrozole, an aromatase inhibitor, compared to clomiphene citrate, a selective estrogen receptor modulator, in achieving live birth in infertile women with PCOS. Treatment- After progestin withdrawal, 750 women will be equally randomized to two different treatment arms: A) clomiphene citrate 50 mg every day for 5 days (day 3-7 of cycle), or B) letrozole 2.5 mg every day for 5 days (day 3-7 of cycle), for a total of 5 cycles or 20 weeks. Dose will be increased in subsequent cycles in both treatment groups for non-response or poor ovulatory response up to a maximum of 150 mg of clomiphene a day (x 5 days) or 7.5 mg of letrozole a day (x 5 days). Statistical Analysis- The primary analysis will use an intent-to-treat approach to examine differences in the live birth rate in the two treatment arms. Anticipated time to completion- A total of 4 years will be required to complete the study after start up; 31 month enrollment period, 5 month treatment period, with 9 month additional observation to determine pregnancy outcomes. This will be accomplished by enrolling \~3.45 women with PCOS per center per month over the enrollment period (N = 7 RMN sites).