Researches have shown that women with polycystic ovary syndrome show higher rates of live births when they are on Letrozole (Femara) an off-label drug to treat infertility as compared to first-line treatment of clomiphene drug.

For this research 750 women who were aged between 18 to 40 years of age and had polycystic ovary syndrome were considered. Out of this 27.5% of women treated with 2.5 mg letrozole daily carried a baby as compared to 19.1% of women treated with 50 mg clomiphene daily.

Richard S. Legro, MD, of Penn State College of Medicine and colleagues reported this study in The New England Journal of Medicine.

Letrozole is marketed under the brand name Femara and is approved to treat hormonally-responsive breast cancer. Although the FDA has not approved letrozole as a fertility aid, but it has been more than a decade since the specialists have been using it as an off-label drug for hormone-related conditions.

On the other hand, Clomiphene is the first-line of treatment for infertility in women with polycystic ovary syndrome.

For the experiment, doses of both the drugs were given in a 1:1 ratio in permuted blocks of two, four, or six, starting on the third day of the cycle for 5 days for up to five menstrual cycles. Maximum daily doses of letrozole were 7.5 mg, and 150 mg of clomiphene, for 5 days.

The researchers concluded that as compared with letrozole women treated with clomiphene showed improvements in biochemical hyperandrogenemia. But on the other hand women treated with letrozole had a sharper decrease in antral follicle count, a slighter increase in endometrial thickness, and lower estradiol levels during the midluteal phase.

Though both clomiphene and letrozole have a risk of serious side effects like patients who took clomiphene were more likely to report hot flashes and patients who took letrozole reported fatigue.