ABSTRACT
Aim of Work: To compare between the effects of clomiphene citrate, tamoxifen and letrozol as ovulation induction agents on endometrial thickness and blood flow as non-invasive parameters of endometrial receptivity in women with polycystic ovaries. Patients and Methods: One hundred and fifty cases meeting the selection criteria were prospectively randomized into three groups 1st Group took 100 mg clomiphene citrate, 2nd Group took 5 mg letrozol and 3rd group took 40 mg tamoxifen. Transvaginal ultrasound and Doppler were done to measure endometrial thickness and endometrial blood flow both pulsatility index (PI) and resistance index (RI) at the day of the maximum follicular growth or at day 20 in the absence of the dominant follicle in the three groups. Results: Significantly thinner endometrium in the clomiphene citrate group as compared to the other two groups and lower impedance in the spiral arteries in both letrozol and tamoxifen groups (P value less than 0.001). Conclusion: Endometrium was thicker with lower impedance in the spiral arteries in both letrozol and tamoxifen groups as compared to clomiphene citrate group. Ovulation and pregnancy rates were not significantly different. Other studies are needed to measure the cumulative results of six cycles, increasing the dose in nonresponders and the incidence of miscarriage.