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Largest Study to Date Finds No Link Between Fertility Pills and Ovarian Cancer

A large analysis of over 13,000 women from the United States, Denmark, Canada, and Australia finds no evidence that fertility pills increase the risk of ovarian cancer. Previous data on the subject have been mixed, causing confusion for prescribing physicians and women who consider the pills to help them become pregnant. Experts say that this newest study should eliminate doubts surrounding fertility pills and ovarian cancer risk.

The analysis, which is the largest study on fertility drugs and ovarian cancer ever conducted, was led by Dr. Roberta Ness, Associate Professor of Epidemiology at the University of Pittsburgh School of Public Health. The study involved re-analyzing data on infertility and fertility drug use from eight studies conducted between 1989 and 1999. Specifically, researchers examined medical data from 5,207 women with ovarian cancer and 7,705 healthy women. While Dr. Ness and her colleagues found that women who had difficulty becoming pregnant were more likely to develop ovarian cancer than women who became pregnant easily, they saw no correlation between the use of fertility drugs and a higher-than-average risk for ovarian cancer.

Experts hope the new study will put to rest any fears that fertility pills cause ovarian cancer. Rather, infertility itself increases the risk of ovarian cancer. Research has shown that women who never have children (or those who have a first child after age 30) are at a higher risk of both ovarian cancer and breast cancer than women who have a first child in their twenties. While the reasons for this increased cancer risk are not completely clear, experts believe that an interruption of menstrual cycles during pregnancy provides a protective effect against ovarian and breast cancer. (Researchers have also found that women who begin menstruating before age 12 or those who do not reach menopause until after age 50 have a higher risk of ovarian cancer and breast cancer than other women).

While Dr. Ness' study rejects the proposed link between fertility pills and ovarian cancer, the study did find one specific factor that increased ovarian cancer: endometriosis. Endometriosis is a condition in which uterine tissue grows outside the uterus in nearby reproductive organs. While fertility pills themselves were not linked to an increased risk of endometriosis in the study, the researchers found that the women who developed ovarian cancer in the study were more likely to suffer from endometriosis compared with the women who did not develop cancer. Experts are still investigating the possible reasons for this connection.

Other risk factors for ovarian cancer:

  • Age
  • Family history
  • Genetic mutations of the BRCA1 or BRCA2 gene
  • Hereditary nonpolyposis colon cancer
  • Early menstruation/late menopause (before age 12/after age 50)
  • Personal/family history of breast cancer
  • Delayed childbirth (after age 30) or never having children
  • Use of talc/talcum powder (controversial)
  • Long-term use of estrogen replacement therapy (10 years or more)

The National Cancer Institute estimates that approximately one out of 57 women will develop ovarian cancer during their lifetime. While ovarian cancer is highly treatable in its early stages, the majority of cases are not diagnosed until late stages when the chances of successful treatment and survival are considerably lower. This is because the symptoms of ovarian cancer are often subtle, or "silent." Women should be aware of the risk factors for ovarian cancer and receive regular physician-performed physical exams to help detect the disease as early as possible.

Additional Resources and References

  • The study, "Infertility, Fertility Drugs, and Ovarian Cancer: A Pooled Analysis of Case-Control Studies," is published in the American Journal of Epidemiology (Vol. 155, No. 3),
  • The January 24, 2002 HealthScoutNews report by Colette Bouchez is entitled "Fertility Drugs' Link to Ovarian Cancer Refuted."
  • To learn more about ovarian cancer, please visit