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
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.