Letrozole Versus Clomiphene Citrate for Superovulation in Intrauterine Insemination Cycles - Retrospective Comparative Study Conducted in the Department of Reproductive Medicine, Mahatma Gandhi Medical College & Hospital, Jaipur

BACKGROUND Superovulation with intrauterine insemination (IUI) increases the probability of pregnancy by increasing number of oocytes and sperm density. The main oral agents used for superovulation are clomiphene citrate and letrozole. Clomiphene citrate a selective estrogen receptor modulator with predominant antiestrogenic action has adverse effects on endometrium and cervical mucous. Letrozole an aromatase inhibitor acts by reducing estrogen production by blocking androgen conversion to estrogen in ovary and peripheral tissues without affecting endometrium and cervical mucous. We wanted to compare the efficacy of letrozole v/s clomiphene citrate as first line ovulation induction drug in infertile patients undergoing IUI. METHODS Based on the inclusion and exclusion criteria, we included 160 patients in our study. They were divided into two groups of 80 each based on the drug given for ovulation induction. The drug was given for 5 days from D3 to D7 of menstrual cycle. IUI was done 38 - 40 hours after trigger and after confirmation of ovulation by sonography. RESULTS The mean age, body mass index (BMI), duration of infertility, type and cause of infertility in both groups were similar. Ovulation rate was 85 % in letrozole group and 71.25 % in clomiphene citrate group, which was statistically significant (P0.035). There was no statistically significant difference between endometrial thickness and total days till ovulation between two groups. Monofolliculogenesis and clinical pregnancy rate were statistically significantly higher in letrozole group. CONCLUSIONS Our study shows that letrozole has better pregnancy rate in comparison to clomiphene citrate (C. C.) in IUI cycles with less risk of anovulation, thin endometrium and multi follicular growth. KEY WORDS Clomiphene Citrate (C.C.), Letrozole (LTZ), Ovulation Induction (OI), Intrauterine Insemination (IUI)