Letrozole in Stimulated IVF Cycles

In-vitro fertilization (IVF) is the treatment of choice for couples with prolonged infertility. The treatment usually involves hormonal stimulation of the ovaries by follicle stimulating hormone (FSH), followed by surgical removal of eggs which are then mixed with sperm in the laboratory to create embryos. The success rates of IVF treatment remain unsatisfactory and are no longer increasing. One of the reasons is an adverse effect of high serum estradiol levels following FSH stimulation on the lining of the uterus. Letrozole is a drug used in the prevention of recurrence of breast cancer because of its action to reduce the intra-ovarian aromatization of androgens to estrogens. It is now increasingly used for ovulation induction and is as safe as clomiphene citrate. Use of letrozole during standard ovarian stimulation for IVF producing adequate numbers of oocytes with physiological levels of estradiol may increase the present success rate of standard IVF treatment. The aim of this randomized study is to compare the live birth rate of FSH alone versus combined FSH and letrozole used for ovarian stimulation in IVF treatment.