Interestingly, the drug provided higher birth rates than clomiphine citrate, an ovulatory stimulant primarily used for treating PCOS –related infertilityMeagan/Flickr

A drug used to treat breast cancer can help women with a common hormonal disorder to become pregnant, according to a new study.

A study by the Penn State College of Medicine found that letrozole, a drug used to treat early breast cancer in postmenopausal women, was highly promising for treating infertility in women diagnosed with polycystic ovary syndrome (PCOS). Interestingly, the drug provided higher birth rates than clomiphene citrate, an ovulatory stimulant primarily used for treating PCOS –related infertility.

PCOS is a common disorder in women that leads to irregular menstrual periods, acne, obesity and excess facial and body growth. Data shows that about one in 15 women across the world is affected by this disorder. The condition impairs fertility and leads to problems in becoming pregnant. The high level of insulin resistance associated with the disorder is one of the main factors that cause infertility. The excess production of insulin in the body leads to additional production of testosterone in the ovaries.

The condition can also affect a woman's heart, blood vessels and appearance, according to the

The study included 750 infertile women with PCOS. All the women, aged between 18 and 40, were trying to become pregnant. During the trial, the women received either clomiphene or letrozole for five cycles. Lead author of the study Richard Legro and colleagues increased the drug dosage after each cycle. Letrozole intake was associated with higher ovulation rates and live birth rates (27.5 percent) than the other drug (19.1 percent).

However, twin pregnancies were higher in clomiphene citrate group (6.9 percent) than in women who took letrozole (3.9 percent). Fatigue and dizziness were the two side effects associated with letrozole intake.

Findings of the study are particularly important as clomiphene citrate offers only limited benefits for treating PCOS.

"Clomiphene has its drawbacks," Legro, said in a news release. "It's 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."

The study has been published in the New England Journal of Medicine.

Previous research has shown some other factors that help treat infertility in women with PCOS, including consumption of a high calorie breakfast and taking cinnamon supplements.

The diabetes drug metformin and gonadotropins hormone shots are some other medications, apart from clomiphene citrate and letrozole, used to treat PCOS- related infertility in women. According to the health experts from NIH, when all the other drug treatments fail, ovarian drilling can be tried to produce positive results.