Letrozole has been shown to improve the odds of conception in women with PCOS, according to a new study.

Women with polycystic ovary syndrome (PCOS) have statistically had a much more difficult time trying to conceive. PCOS is a hormonal imbalance issue that interferes with ovulation. It affects between five and 10 percent of women in their reproductive phase, and can cause small cysts on ovaries and irregular periods, in addition to problems conceiving.

According to the Centers of Disease Control and Prevention, PCOS is the most common reason for female infertility.

For decades, the typical treatment for infertility in women with PCOS has been the administration of clomiphine citrate. This drug, however, has its limitations.

Richard Legro, lead study author and professor of obstetrics and gynecology, isn’t entirely confident in clomiphine citrate for dealing with female infertility.

“Clomiphine has its drawbacks. 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,” said Legro in a statement.

The study’s researchers compared clomiphine citrate with letrozole to identify which of the two was more effective in rectifying infertility in women with PCOS. They analyzed 750 women with PCOS between the ages of 18 and 40 who wanted to get pregnant. The group of women who took letrozole had a better chance of conceiving, compared to the clomiphine citrate group. Those on letrozole had a 27.5 percent chance of conception, and those on clomiphine citrate had a 19.1 percent chance. The rate of ovulation was also higher in the letrozole group.

The findings of the study are published in the New England Journal of Medicine.