Polycystic ovary syndrome, or PCOS, a type of endocrine disorder that occurs when a woman's hormones get out of balance, is the leading causes of infertility among women in the U.S.
The condition, which is marked by abnormally high levels of the male hormone androgen, irregular menstrual periods and the development of small cysts on the ovaries, affects up to 10 percent of women of reproductive age, who may need to take medications to boost their fertility.
For patients with PCOS, doctors often prescribe clomiphine (Clomid) to help improve their chances of giving birth but a new study suggests that a drug used for treating breast cancer may be more effective in boosting fertility in women suffering from polycystic ovary syndrome.
Researchers found that the drug letrozole (Femara), which blocks the production of the hormone estrogen, is associated with better ovulation and conception as well as improved birth rates in PCOS patients.
For the new study published in the New England Journal of Medicine on July 10, Richard Legro, from the Penn State University's College of Medicine, and colleagues randomly assigned 750 women with PCOS to take either clomiphene or letrozole to compare the efficacy of the two drugs as treatment for infertility.
Clomiphine citrate, which works by stimulating ovulation, is currently the standard infertility treatment given to women with polycystic ovary syndrome but the drug is linked with unwanted side effects including hot flashes and mood changes. The treatment is also associated with high rates of multiple births.
The researchers observed that ovulation rate was higher with women who used letrozole (62 percent) than in women who used clomiphene (48 percent). They also found that nearly 28 percent of the women who took letrozole had babies after five cycles while only 10 percent of the women who used clomiphene did. Women who used letrozole also tend to have reduced likelihood of giving birth to twins. Only three percent of the letrozole users had twin pregnancies compared with seven percent of the women who took clomiphene.
"As compared with clomiphene, letrozole was associated with higher live-birth and ovulation rates among infertile women with the polycystic ovary syndrome," the researchers reported.
Legro, however, said that it isn't yet clear if letrozole could lead to more birth defects compared with other drugs.
"We will need other studies to show that the rates of birth defects are actually low -- lower than we would expect in an infertile population," Legro said.
