All women received the same regimen of ovarian stimulation using Letrozole (Femara; Novartis pharma AG, Basle, Switzerland) 2.5 mg tab twice daily for 5 days starting from cycle day 3. Transvaginal ultrasound scan (TVS) was performed daily from cycle day 9 and a total of 10,000 IU of hCG (Epifasi, EPICO) was administered to those in whom at least one ovarian follicle was ≥18 mm in size. On the day of hCG administration women were randomly categorized into two groups according to a computer generated random numerical table. Envelopes containing the allocation information were chosen sequentially by patient herself in presence of her husband. Group A received FSH (urofollitropin; Fostimon, IBSA, Bazel, Swiz; 75 IU amp) 150 IU injected once on day of hCG injection and group B received no FSH on day of hCG injection. Intrauterine insemination was performed 36 hours after HCG injection. Women in both groups received luteal phase support in the form of vaginal progesterone, (Prontogest 400 mg Vaginal Pessaries, IBSA) twice a day, starting from the day after IUI and continued till the eighth week, if the pregnancy test was positive.Two weeks later, quantitative ßhCG was estimated to diagnose chemical pregnancy. However, TVS was performed 4 weeks after positive pregnancy test to confirm clinical pregnancy by the presence of gestational sac with fetal echoes and pulsation and to exclude ectopic pregnancy. All women enrolled in the study underwent the study protocol for three consecutive cycles unless got pregnant.