A Breast Cancer Drug May Help Women Become Pregnant

For women with polycystic ovary syndrome (PCOS), getting pregnant is tough. The disorder effects 5-10% of women, and interferes with their sex hormones and menstrual cycles, sometimes preventing women from ovulating altogether. Some women also develop ovarian cysts and have trouble getting pregnant.

The drug clomiphine citrate has been the go-to treatment because it spurs ovulation, but it’s not perfect: it’s just 22% successful with up to six cycles of treatment; it has a high rate of multiple pregnancies; and it can cause side effects like mood swings and hot flashes. Clearly, women need another option.

In a new study published in the New England Journal of Medicine, the researchers looked at 750 infertile women with PCOS and randomly assigned them to either take clomiphene or a newer drug called letrozole—which is also used to treat breast cancer in a different dose—for up to five cycles. The results show that the women taking letrozole had a significantly higher rate of births at 27.5% compared to 19.1% for the women on clomiphene. The women receiving letrozole also had higher ovulation rates and fewer twin pregnancies. Birth defects for women on both medications were rare.

The findings are encouraging for women looking for better options to increase fertility, but more research is needed.