As part of Breast Cancer Awareness Month, we’ll be exploring the intersections of cancer, fertility, and women’s health throughout October. See more.

Cancer and fertility

As we discussed a few weeks ago, the most comprehensive study of its kind confirmed that there’s no link between fertility medications and an increased risk of breast cancer—which is great news for women thinking about freezing their eggs, who take these fertility medications as part of the process.

This study is just the most recent to join many others, which collectively have lead the American Society for Reproductive Medicine (ASRM) to conclude that fertility medications don’t increase women’s risk of any cancers.

In fact, the relationship, unfortunately, often goes the other direction: cancer, or more accurately cancer treatments, can put a woman’s fertility at risk, even years after the cancer is gone.

This usually happens as a result of one of three treatments:

Surgery. For women with cancers of the reproductive system, doctors may determine that the best course of treatment is to remove the affected ovary (or ovaries), uterus, or Fallopian tubes. Obviously, removal of a crucial part of the reproductive system can make it more difficult or impossible for a woman to conceive on her own.

Additionally, even if the whole organ isn’t removed, surgery to remove a tumor or tumors can cause scarring to the reproductive system that can affect ovulation or the ability to carry a pregnancy.

Chemotherapy. Chemotherapy works by using medications called cytostatics and cytotoxins to attack cancer cells (and other cells that divide quickly) kill them or and prevent them from dividing—that’s why people undergoing chemo can lose their hair, as quick-dividing hair cells are attacked by the meds. But the medication is usually administered “systemically,” meaning through the bloodstream to the entire body, so it can also damage other cells along the way.

Because a woman is born with all the eggs she’ll ever have—all stored in her ovaries—all of her eggs are at risk of damage from chemotherapy drugs. If the eggs’ DNA is damaged (in other words, if the egg becomes genetically abnormal and therefore low quality) it may not fertilize or may result in miscarriage or birth defects.

Radiation therapy. Radiation involves high-energy rays directed at the cancer, in hopes of killing those cells. But by extension, this treatment can also damage parts of the body surrounding the cancer as well, including destroying some or all of a woman’s egg cells or causing scarring in her uterus, Fallopian tubes, cervix, or elsewhere in the reproductive organs.

The location of a woman’s cancer affects whether or not radiation treatment will be absorbed by the ovaries and damage the eggs; women with cancer in the abdominal or pelvic areas are most at risk of infertility from radiation therapy. And because ovulation begins in the pituitary gland in the brain, radiation to that area can affect fertility, as well. While not all women experience infertility immediately following treatment, the fact that radiation destroys eggs in the ovaries can also cause a cancer survivor to go into menopause earlier.

Cancer and egg freezing

All of these treatments can affect fertility. And in each case, fertility preservation—AKA freezing eggs or embryos—offers an option for women who might want to be mothers after they’re cancer-free.

Egg freezing works by retrieving healthy eggs from a woman’s ovaries, freezing them, and storing them. (Learn more about the process.) So eggs retrieved and frozen before cancer treatment will be free of any damage or destruction introduced by the treatments—the eggs will be frozen in time and health. Then, later, she can thaw and fertilize those eggs, creating an embryo that will be transferred into her uterus in hopes of a pregnancy (a process called in vitro fertilization or IVF).

If a woman’s ovaries or Fallopian tubes are damaged or removed as a result of her cancer, she can still get pregnant through IVF, because this process bypasses the ovaries and the Fallopian tubes altogether. Even if her uterus is damaged or removed, she can have a biological child using her eggs and a surrogate. Science is amazing that way!

Read one woman’s story of freezing her eggs before breast cancer treatment—and using those eggs to have a child five years after being deemed cancer-free. And learn more about our partnership with LIVESTRONG Fertility, bringing information about and access to egg freezing to more women diagnosed with cancer.