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 letrozole 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.