Women undergoing IVF will often take an ovulation-inducing drug such as clomiphene in order to produce enough eggs for extraction.
Following the extraction, the eggs are fertilized in culture and the resulting embryos implanted in her uterus a few days later.
For women who do not become pregnant from the cycle of IVF, the fertility drugs they took may still have beneficial health effects.
Research out of the National Cancer Institute found that women who received fertility drugs but did not conceive had a significantly reduced risk of young-onset breast cancer than women who did conceive.
Experts believe that the effect may lie in the type of fertility drug prescribed. Most women in the study used clomiphene, which is similar to the chemotherapy drug tamoxifen, and may share some anti-cancer benefits.
Not using the fertility drugs did not increase the risk of cancer above that of the general public.