Breast Cancer & Fertility

While most connections between fertility issues and cancer are regarding cancer of the reproductive organs, some may have questions about the relationship between other, more common forms of cancer and trying to conceive. Here, we'll address any relationship between what is a very common cancer -- cancer of the breast -- and infertility.

Does Being Infertile Put You At Greater Risk?

In general, there is a connection between the amount of exposure a woman has to estrogen and her risk of breast cancer. More and longer exposures to estrogen, whether through a woman's own bodily means or through administered estrogen, generally equal a greater risk. Some of the factors that may relate to women who are experiencing infertility are:

  • Late childbearing age -- having a first child after the age of 30 is related to an increased risk of breast cancer
  • Never having children -- women who have never had children are in general more at risk
  • Early menarche -- having started menstruation before age 12 increases the risk somewhat
  • Long-term hormonal contraception -- using birth control pills for long periods of time increases risk somewhat

Will Using Fertility Treatments Increase Your Risk?

One study comparing women who had undergone IVF versus those who had not found a higher incidence than expected for breast and uterine cancer within 12 months of exposure to fertility drugs with IVF. It should be noted, however, that the overall incidence of breast and ovarian cancer were no greater than expected in the general population. Also, the study found no association between the number of IVF treatment cycles and the incidence of breast, ovarian, or uterine cancer.

The same study found that those with unexplained infertility as a diagnosis had significantly more cancers of the ovaries or uterus, regardless of whether they participated in IVF or not.

Regarding the higher incidence within 12 months of drug exposure, the researchers suggest two possible reasons:

  • early diagnosis may have been made due to patients being closely followed medically for infertility, and
  • fertility drugs used for superovulation in IVF may promote development of pre-existing cancers

To explain the high occurrence of cancers in the unexplained infertility population, the researchers suggest that, perhaps, the underlying cause of their infertility was indeed undetected cancer.

The researchers themselves add that certain variables which may have related impact were not taken into consideration in this study, including

  • parity (related to having given birth before),
  • age at first birth,
  • use of oral contraceptives,
  • age at menarche and menopause, and
  • "other" factors.