Helping women with a common fertility problem

A breast cancer drug may help women with polycystic ovary syndrome achieve a successful pregnancy better than the standard treatment, new research suggests.

Polycystic ovary syndrome is one of the most common causes of infertility, affecting 5 to 10 percent of women of childbearing age. The condition, often linked to diabetes, is caused in part by a hormonal imbalance. In PCOS, the ovaries make high levels of androgens — primarily a male hormone that women also produce, typically in small quantities.

The standard treatment has long been a drug called clomiphene citrate, which stimulates ovulation. But its success rate is limited. It also increases the odds of multiple pregnancies and it has side effects that include hot flashes and mood changes.

But in a national study that included University Health System patients, the estrogen-blocking drug letrozole had better results — 27.5 percent of those taking the drug had successful pregnancies, compared to 19.1 percent taking clomiphene. In addition, the letrozole group had fewer twin pregnancies and fewer hot flashes — although they reported more fatigue and dizziness.

Birth defects were rare in both groups, with rates about the same and comparable to those who conceive without treatment. However more research is needed with larger numbers of babies to fully understand the safety of letrozole, the researchers said.

The study was published last week in the New England Journal of Medicine. The local arm of the study was led by Dr. Robert Brzyski, who has since retired as professor of obstetrics at the UT Health Science Center San Antonio.