Effect of tamoxifen on infertile women with poor response to clomiphen citrate

Background: Clomiphen citrate is the first choice to induce ovulation in patients with infertility. In resistant cases, an alternative such as tamoxifen is administered. Objective: To investigate the effect of tamoxifen on endometrial thickness and ovulation rate of infertile women with poor response to clomiphen citrate. Methods: This was a clinical trial performed at Kosar hospital, affiliated to Qazvin University of Medical Sciences, in 2007. Thirty four infertile women who were treated by a maximum of 150mg clomiphen citrate for 5 days but still with endometrial thickness below 7mm or absence of dominant follicle, considered as resistant cases. The resistant patients were treated with tamoxifen citrate 10 mg for 5 days from 5th to 9th day of menstruation. In case of inadequate response, reflected through the absence of dominant follicle during next periods, the dose of drug was increased to 10-20 mg/day. At the 16th day of menstruation, vaginal sonography was applied to investigate the number and diameter of dominant follicle and endometrial thickness. Data were analyzed using chi-square test and T. test. Findings: Using clomiphen citrate, 6 patients with improper endometrial thickness showed a distinct improvement (5±1.8 mm to 12.1±1 mm, P<0.002). Using 30 mg of tamoxifen, 8 patients (23.4%) were found to have dominant follicle (P=0.008) and 2 cases became pregnant. Conclusion: Tamoxifen may be a good alternative for clomiphen resistant patients in whom it improves the endometrial thickness and in the meantime accelerates the development of dominant follicle before treatment with HMG or surgery.