More than 6 million couples in America each year cannot conceive a child, estimates the National Center for Health Statistics. To improve their chances of becoming pregnant, millions of women turn to fertility drugs. However, some studies have suggested that fertility drugs may promote ovarian cancer. What do experts think of this concern? If you are one of these women, what should you be aware of?
How Fertility Drugs Work
In infertility cases, 66% occur in men or in both partners. The remaining 33% stems from a problem in the woman’s reproductive system. Ovulation disorder is a common cause. This means that the ovaries do not work properly. Ovaries normally make hormones and store eggs.
With ovulation disorder, there may be a lack of special hormones released by the pituitary gland. These hormones are called follicle-stimulating hormone (FSH) and luteinizing hormone (LH). They help eggs grow and release from the ovaries.
Fertility medications such as Clomid (clomiphene) and Pergonal (menotropins) are used for this type of infertility. They mimic the actions of these hormones.
Research About the Link Between Fertility Drugs and Ovarian Cancer
Over a decade ago, studies began suggesting that the use of fertility drugs could increase ovarian cancer. This raised great concern.
1992. The first study to suggest a direct link was published in 1992 in the American Journal of Epidemiology. Researchers found that women who used fertility drugs and failed to conceive had a higher risk for ovarian cancer. Interestingly, women who used fertility drugs and conceived did not have a higher cancer risk. It was unclear whether the results of this study had anything to do with the fertility drugs or something related to infertility.
One theory stemmed from the strong evidence that certain factors associated with ovulation protect against ovarian cancer. Pregnancy and birth control pills are both associated with a decreased risk of ovarian cancer. They also result in a decrease in the number of times a woman ovulates. On the other hand, fertility drugs cause extra ovulations. Ovulation irritates the lining of the ovaries. So it was thought that these extra ovulations might promote cancer.1
2001. Another theory suggested that the culprit might be certain hormones that increase with the use of fertility drugs. A study published in 2001 in Fertility and Sterility addressed this question. The researchers exposed laboratory ovarian cells to follicle-stimulating hormone (FSH) and human chorionic gonadotropin(hCG), a hormone that naturally increases during pregnancy.2
The study found that FSH did not increase the growth of ovarian cells, and the hCG actually caused cell growth to slow down. The researchers concluded that pregnancy might protect against ovarian cancer. This might be due to higher hCG levels, not because pregnancy blocks ovulation.
2002. A major study published in the American Journal of Epidemiology found no link between fertility drugs and ovarian cancer. The study, however, did find an association between ovarian cancer and infertility itself.3
The study found that women who spent more than 5 years trying to conceive were at a higher risk for ovarian cancer. Women who were infertile due to endometriosis were at highest risk. Endometriosis is a condition in which tissue from the uterus grows outside of it. Commonly, it adheres to the ovaries. When this happens, it can interfere with their function.
2004. A study published in in Obstetrics and Gynecology also found generally reassuring results. This study found no strong link between fertility drugs and ovarian cancer. There was, however, a slight increase among women who had used the drugs many years ago. Although this was not thought to be significant, the researchers called for continued monitoring of long-term risks.4
Investigators at this time do not believe that either a family or personal history of ovarian or breast cancer should prevent a woman from using fertility drugs. However, a woman who may be at high risk because of such a history may consider genetics counseling, and possibly enrolling in a screening program.