By the time they were enrolled in the study, all women had already completed 5 ovulatory cycles of Clomiphene citrate induction (in a dose of 100 mg/ day in two divided doses starting from day 3 of the cycle for 5 days) but without conception (clomiphene citrate failure) with thin endometrium (<8mm) in at least 3 cycles. Ovulation was documented sonographically, and with day-21 serum progesterone exceeding 5 ng/ ml in all cases.