Breast cancer drug Letrozole can help increase chances of pregnancy in women suffering from polycystic ovary syndrome (PCOS).

Researchers at the Penn State College of Medicine have found that letrozole use results in higher birth rates in women with PCOS as compared to standard treatment for infertility in these women.

PCOS is a common hormonal condition affecting women of reproductive age and is an important cause of infertility. Some common symptoms of the condition include absence of regular periods, excess body or facial hair and polycystic ovaries. These women have high levels of hormone androgen and have trouble conceiving.

Doctors currently prescribe Clomiphine citrate - a drug that stimulates ovulation - to restore fertility in women with PCOS. But, the drug has its drawbacks.

"It's (Clomiphine citrate) only 22 percent successful with up to six cycles of treatment in producing a successful birth, it has a high multiple-pregnancy rate in comparison to unassisted conception, and it has side effects including hot flashes and mood changes." said Richard Legro, professor of obstetrics and gynecology and lead author on the study, according to a news release.

Letrozole is approved for being used in the treatment of breast cancer in old women. The drug works by decreasing the levels of estrogen produced in the body.

For the study, researchers compared the effects of the two drugs on 750 infertile women with PCOS. Participants were aged between 18-40 years and wanted to conceive. Researchers randomly gave women either clomiphene or letrozole. The medication were given over five cycles with increase in dosage in each cycle.

Researchers found that the rate of live birth was higher in women who were given letrozole than in women on clomiphene (27.5 percent versus 19.1 percent). Ovulation rates were also higher in women on letrozole.

Women who used letrozole had low dizziness and fatigue than other women in the study. Rate of twin babies and other birth complications were also lower in women who took the breast cancer drug.

The study is published in the journal New England Journal of Medicine.