Breast Cancer and Fertility: What You Need to Know

Learn how breast cancer treatments can affect reproductive health — and what options women have for fertility preservation.

An increasing number of women are being diagnosed with breast cancer at younger ages, when they are starting or growing their families. Unfortunately, breast cancer treatments can have significant effects on fertility, presenting unique challenges and additional stress for these patients. Studies show that infertility concerns can affect treatment decisions, adherence to treatment, quality of life, and even long-term disease outcomes in younger women. In honor of Infertility Awareness Week (April 19-25), BCRF is shedding light on these issues.

It is important to note that undergoing breast cancer treatment does not always cause infertility. Thanks to research conducted by BCRF investigators and others, more and more younger survivors can preserve their fertility. Their results were published in the journal Cancer in 2023 and showed that most participants diagnosed at age 40 and younger with stage 0 DCIS to stage III breast cancer were able to get pregnant, and the majority had a live birth.

Read on for more about how breast cancer treatment affects fertility, fertility preservation for breast cancer patients, fertility after breast cancer treatment, and more.

Can breast cancer affect fertility?

Breast cancer itself does not impact your ability to have children because it doesn’t typically damage organs related to reproduction (such as the uterus and fallopian tubes), or those involved in hormone production (such as the ovaries and pituitary gland). But breast cancer treatments such as chemotherapy and hormone therapy can affect the ovaries and hormone production, which can lead to temporary or permanent infertility.

The odds of getting pregnant following treatment also depend on your reproductive health in general. Conditions like endometriosis or polycystic ovary syndrome (PCOS) can interfere with conception. So, your baseline fertility status and whether you’ve had trouble getting pregnant in the past plays a role. In addition, certain lifestyle factors such as obesity and smoking can lower your chance of conceiving. Age is also important. Women who receive cancer treatment before age 35 are more likely to become pregnant after treatment because in general, younger women have more eggs than older women.

How breast cancer treatment affects fertility

Breast cancer treatment can impact your ability to get pregnant to varying degrees. Whether your fertility will be affected is based on multiple factors, including the type and dosage of treatment you receive and the amount of time that has passed since treatment. Here is more information by treatment.

Chemotherapy

Chemotherapeutic drugs may compromise fertility by damaging ovarian follicles, which contain egg cells essential for reproduction. Certain types of medication, notably alkylating agents such as cyclophosphamide, are a greater threat to fertility than other chemotherapy drugs because they can stop the ovaries from developing mature eggs and producing estrogen. They can also cause primary ovarian insufficiency (POI), when a woman’s ovaries stop working before age 40.

The good news is that most younger breast cancer patients who undergo chemotherapy avoid POI. A meta-analysis of five studies of this patient group showed that the rate of POI was 31 percent. However, your personal risk of infertility may be higher if, for instance, you’re treated with high doses of chemotherapy or multiple chemotherapy drugs at the same time.

Hormone therapy

Hormone therapy, or endocrine therapy, is prescribed to patients with hormone receptor-positive breast cancer to reduce recurrence and mortality. These medications, which include tamoxifen and toremifene, do not directly damage the ovaries, but can disrupt menstrual cycles and delay childbearing, which may reduce fertility over time.

Hormone therapy can also interfere with family planning because treatment can take anywhere from five to 10 years, forcing a delay in childbearing until treatment is complete. By the time they finish, younger breast cancer survivors may be experiencing a natural age-related decline in fertility. However, BCRF investigator Dr. Ann Partridge co-led a clinical trial  (the POSITIVE trial) that found that many women with early-stage breast cancer are able to pause hormone therapy for up to two years to try to get pregnant without raising the risk their cancer will recur in the short term. Many participants were able to become pregnant and deliver a healthy baby during their pause in treatment.

Radiation therapy

Radiation therapy for breast cancer does not increase the risk of infertility. Unlike chemotherapy, which affects the whole body, radiation therapy is typically targeted to the breast. Even though small amounts of radiation can scatter to other parts of the body, it’s not enough to cause ovarian failure. Radiation to the ovaries, however, can cause infertility by damaging ovarian follicles and eggs.

How soon can you start trying for a baby following breast cancer treatment?

The answer depends on several factors, such as the amount of time needed to recover and how long it takes for the medications you took to clear your body. The safest timing varies by cancer type, recurrence risk, and treatment plan; many clinicians discuss waiting about two years after treatment, but this is individualized.

Fertility preservation for breast cancer patients

There are several fertility preservation procedures available to premenopausal women diagnosed with breast cancer — none of which appear to raise the risk of breast cancer recurrence. It’s best to undergo fertility preservation before you start treatment. You and your doctor should discuss options right away following diagnosis. Below are some of the most common.

Embryo/oocyte cryopreservation. These procedures are standard methods for preserving fertility and are often the first strategies your doctor will discuss. Embryo cryopreservation involves harvesting eggs, fertilizing them with sperm, and freezing them to be implanted later.

In oocyte cryopreservation (egg freezing), unfertilized eggs are harvested and frozen. It is ideal for women who don’t currently have a partner and don’t want to use donor sperm. Embryo and egg freezing are established fertility-preservation methods, and success depends on age at retrieval, the number and quality of eggs or embryos stored, and the clinical outcome.

You’ll need to be on ovary-stimulating medications for two to three weeks before undergoing these procedures so your doctor can retrieve mature eggs. Therefore, embryo/oocyte preservation may not be recommended if you need to start cancer treatment immediately.

Ovarian suppression. If chemotherapy is part of your treatment plan, your doctor may recommend taking a type of medication called a gonadotropin-releasing hormone agonist (GnRH). This class of drugs can help protect fertility by suppressing ovarian activity, which is thought to minimize damage to the ovaries caused by chemotherapy. Results from the aforementioned 2018 metanalysis showed that only 14% of patients temporarily taking GnRH experienced POI.

Ovarian tissue cryopreservation. In this procedure, a surgeon removes egg-producing tissue (the ovarian cortex) from the ovary. The tissue is then frozen, stored, and reimplanted once treatment is complete. Ovarian tissue cryopreservation is most likely to be offered to girls who have not reached puberty and adult women who must start treatment for breast cancer immediately. It can be used as a stand-alone treatment or in combination with other cryopreservation procedures.

Safety concerns

Some women worry that pursuing fertility preservation could affect their chance of surviving breast cancer. But even accounting for the slight delay in starting treatment that is necessary for some fertility preservation procedures, a study co-authored by Dr. Partridge found that there is no difference in invasive disease-free survival (meaning the cancer did not come back or spread, and no new cancer developed) at five years between women who do and do not opt for fertility preservation.

Previously, there was some concern regarding the use of ovary-stimulating medication in women with estrogen receptor-positive breast cancer because these drugs temporarily expose patients to higher estrogen levels. While research in this area is limited, the available data support the safety of ovary-stimulating medications in these patients.

Emotional and practical considerations

Unfortunately, women diagnosed with breast cancer face several barriers to undergoing fertility preservation. Affordability is a major concern for many, as the cost of fertility preservation procedures can be very high. Those who don’t have health insurance or who have public health insurance — more common among Black and Hispanic women — may be unable to afford these procedures.

Access to and utilization of fertility procedures is another challenge that also disproportionally affects women of color. Compared to white women, Black and Hispanic women attempt to conceive for a longer period before seeing a reproductive specialist and face greater difficulty in obtaining an appointment, taking time off from work, and paying for treatment.

Pursuing fertility preservation can also come with emotional challenges. Women may struggle to make a choice because they must do so during the short and very emotional time immediately following diagnosis. Both the American Society for Reproductive Medicine and the American Society of Clinical Oncology recommend psychological counseling before treatment for patients interested in fertility preservation. Counseling is associated with improved quality of life and can reduce long-term regret and dissatisfaction around fertility decisions.

Talking to your doctor about fertility

If you’re premenopausal and have been diagnosed with breast cancer, it is important to discuss fertility concerns with your doctor as soon as possible. Even if they don’t bring up the subject, be sure to mention these concerns before treatment begins.

If you’re interested in starting or growing your family after treatment, your doctor will likely refer you to a fertility preservation specialist. This person will talk to you about your disease and prognosis, how your treatment plan may affect fertility, the likelihood of pregnancy and its safety and outcomes, and more. They will also be able to discuss the available options for fertility preservation so that you can make a fully informed decision.