How breast cancer affects a woman’s fertility

Women with breast cancer have tough decisions to make. But pregnant women and those who want to have children down the road have even more to consider.

Soon-to-be and hope-to-be mothers must weigh how the intense drugs and procedures used to kill cancer will affect their fetuses or future fertility. Some treatments are easier on the body, but almost all come with some risk.

“A large portion of the chemotherapy regimen includes medications that are fairly toxic to the ovaries,” says Dr. Amber Cooper, a fertility specialist at Washington University School of Medicine in St. Louis. “So there can be a significant impact on a woman’s ovarian function, both for future hormone production and future fertility.”

What to expect

Cancer treatment’s long-term effects on fertility vary dramatically depending on age. Research shows survivors in their 20s stand a good chance of getting pregnant without many complications. But for women in their late 30s or 40s, treatments may be too much for ovaries to handle, sometimes even triggering early menopause.

Cooper says women have many options for a successful pregnancy and birth, but it’s crucial to talk about it right after diagnosis. Women can freeze eggs or embryos to use later, and it can all happen before treatment begins and hormone levels fluctuate.

“In our center, we get a call about a cancer patient, get them in 24 to 48 hours, and we can often freeze eggs or embryos as quickly as eight to 12 days,” she says.

Women who get diagnosed while pregnant deal with a different set of complications.

Dr. Shannon Pulhalla is an associate professor of medicine at the University of Pittsburgh Medical Center’s Magee-Women’s Hospital. She says timing is everything for pregnant women with breast cancer.

Chemotherapy is out of the question, she says, because so much crucial development happens during the first trimester. The effects of these drugs drastically damage a child’s growth. But other drugs are safer in the second and third trimesters. Unfortunately, there are many unknowns.

“Certain drugs we have more data on; for others, we have less data and don’t know if they’re safe or not,” Pulhalla says.

Lactation limitations

New moms with breast cancer also often miss out on breastfeeding. For survivors, sometimes treatment has rendered them unable to produce milk.

When a woman is diagnosed while pregnant, often she will start chemotherapy shortly after delivering her baby.

“If that’s the case, most of the time breastfeeding would not be recommended because some chemotherapy drugs could accumulate in the breast milk and be passed to the baby,” Cooper says. 

In some cases, women breastfeed for a short time before they start a chemo regimen, she says.

Survivors who complete treatment and get pregnant later can breastfeed if they are able. In other instances, breastfeeding isn’t possible because a woman has chosen to have her breasts removed, Pulhalla says.

A breast cancer diagnosis doesn’t necessarily take motherhood off the table. Each case is different, so it’s important to explore options. Reproductive specialists can give women the most complete answers for their case, and with modern medicine, they can offer some hope, too.  

“Occasionally, there will be very specific situations where it’s just not safe or not feasible and can’t happen,” Pulhalla says. “But everyone should have a discussion.”