Femara is a drug used to control breast cancer in menopausal women that works by blocking the use of the hormone estrogen. Although it was formulated for inhibiting the growth of some breast cancers, Femara has been used for other purposes as well. It has an added effect of increasing fertility, so some doctors prescribe it for this purpose alone.

However, because the medication wasn't created to be used as an aid to conception, there have been a number of consequences of its use in this capacity. Femara was first prescribed for ovulation by doctors in 2001 and since then the drug maker Novartis has received at least 13 reports of complications in pregnancy, with almost a third of these dealing with fetal injury and birth defects.

Regardless of its tendency to increase fertility, there have been no extensive tests to explore the effects of Femara on pregnancies in humans, since the drug was only approved to fight cancer. Animal testing, however, shows that even in small doses, Femara can harm embryos, fetuses, and newborn babies. Despite this disturbing data, fertility clinics and physicians continue to prescribe the breast cancer drugs for women wanting to conceive.