Comparison of Letrozole and Clomiphene Citrate Efficacy along with Gonadotrophins in Controlled Ovarian Hyperstimulation for Intrauterine Insemination Cycles

BACKGROUND We performed this study to investigate and compare the effects of Letrozole and gonadotrophins versus Clomiphene Citrate and gonadotrophins in women undergoing superovulation for Intrauterine Insemination (IUI). METHODS We performed this prospective cohort study at Australian Concept and Fertility centre, Karachi Pakistan. Women younger than 40 years of age with patent fallopian tubes and infertility of more than 2 years in duration who were undergoing IUI and gonadotrophins therapy were divided into two groups, one received Letro-zole for 5 days and another received Clomiphene Citrate for 5 days. RESULTS All 500 IUI treatment cycles conducted from March 2008 to March 2010 were included. Patients co-treated with Letrozole required fewer gonadotrophins administrations (median difference, 300 IU (95% confidence interval (CI), 225-375 IU), developed more follicles larger than 14 mm (median difference, 1 follicle, 95% CI, 1-2 follicles), and had a thicker endometrium (median difference, 1 mm, 95% CI, 0.4-1.6 mm). The pregnancy rate was not significantly different between two groups (11% vs. 12.6%). CONCLUSION The addition of Letrozole to gonadotrophins decreases gonadotrophins requirements and improves endometrial thickness, without a significant effect on pregnancy rates. An improved pregnancy rate has been observed in older age group, >35 years with Letrozole.