Fertility Drugs Don't Cause Ovarian Cancer

By Margarita Nahapetyan

Fertility drug use does not increase women's risk of developing ovarian cancer, according to a large new study by Danish scientists. The results of the research should reassure women who have been treated for infertility, but who still have concerns about the safety of the drugs for their future health.

Very often, the reason for a woman's infertility is caused by her ovaries not being able to release eggs regularly or at all. Fertility drug treatment can stimulate the ovaries to release eggs, allowing them to be fertilized by sperm.

Some previous studies have suggested that fertility drugs increase a woman's risk of ovarian cancer, especially if she undergoes several cycles of fertility drug treatment. But present findings have not found any evidence of an increased risk, even among women who have used these drugs multiple times.

In the new study, Danish Cancer Society researchers in Copenhagen, evaluated the medical records of 52,362 women referred to fertility Danish clinics with infertility problems from 1963 to 1998. Of all the women, 156 developed ovarian cancer. The authors said this was found mostly in women followed up for 15 years or more and was difficult to be certain about, therefore more research would be needed on this.

After adjusting for risk factors associated with the cancer, the investigators analyzed the impact of four different fertility drugs on ovarian cancer risk, such as clomifene, gonadotrophins, human chorionic gonadotrophin and gonadotrophin releasing hormone.

The results showed that none of the four groups of fertility drugs which have been in use for many years now, were associated with an increase cancer risk. It also found no increased risk among women who had 10 or more cycles of fertility drug treatment or among women who never managed to become pregnant.

The researchers also found that, compared to having no children, the risk of developing ovarian cancer decreased the more children a woman had. The risk of cancer was not affected by the women's age at the birth of the first or the last child, their use of oral contraceptives, or the reason of their infertility.

"In a society where infertility in women and maternal age at birth of the first child are increasing, the unfavorable effects of fertility drugs (for example, a possible small increase in risk of ovarian cancer) should be balanced against the physical and psychological benefits of a pregnancy made possible only by the use of these drugs," the lead researcher of the study, Dr. Allan Jensen, PhD., assistant professor of cancer epidemiology, wrote in the paper.

However, many of the women in the study had not reached the age for ovarian cancer, so the researchers intend to continue to monitor their health. "As many of the women in our cohort have not yet reached the usual peak age for ovarian cancer, we will continue to monitor the risk to try to establish a more definite link between use of fertility drugs and risk of ovarian cancer," Dr. Jensen said.

Penelope Webb, of the Queensland Institute of Medical Research, wrote in an accompanying editorial that the findings are reassuring and provide further evidence that the use of fertility drugs does not increase a woman's risk of ovarian cancer. She also said the results of the study are very valuable, with the increasing number of women these days seeking fertility treatment, and recommended that clinicians should take time to discuss this matter with their patients in order to properly inform the women.

"Some women who take fertility drugs will inevitably develop ovarian cancer by chance alone, but current evidence suggests that women who use these drugs do not have an increased risk of developing ovarian cancer."

The study was published in the British Medical Journal (BMJ).