Fertility, birth control and pregnancy in breast cancer survivors: Answers to common questions

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The following is an excerpt from “Beyond Breast Cancer: A Mayo Clinic Guide to Healing and Wellness,” a supportive, practical guide to life after diagnosis and initial treatment for breast cancer.

About 10% of breast cancer survivors are diagnosed at an age when they may have been looking forward to having children. If you’re in this group, you may be wondering about whether it is possible and safe to have children after being treated for breast cancer, or whether your children might be affected by your history of breast cancer.

Or maybe pregnancy isn’t on your radar yet — or you weren’t planning on ever having kids — and you have questions about what birth control you can use, especially if you can no longer use hormone-based contraception.

Many people have concerns about their reproductive health as they enter the survivorship phase of their cancer journey. While statistics show that, on average, breast cancer survivors are 40% to 60% less likely to get pregnant than people who didn’t have cancer, the good news is that many breast cancer survivors can and do get pregnant and deliver perfectly healthy babies. And for those looking to avoid pregnancy, there are safe and effective birth control options.

Sometimes it can feel as if topics such as fertility and contraception don’t get the same attention as other aspects of survivorship. Addressing these topics is a crucial component of any survivorship plan and a key factor in your physical and emotional well-being. If no one on your health care team has discussed these topics with you yet, don’t hesitate to start the conversation.

Below are some of breast cancer survivors’ common questions regarding birth control, fertility and pregnancy.

What kind of contraception can I use as a breast cancer survivor?

Research has found that unplanned pregnancies among breast cancer survivors are common. The reason for that could involve any number of factors. There’s a misconception among survivors that because breast cancer treatments can damage ovarian function and cause infertility, pregnancy is next to impossible.

A recent study out of the United Kingdom highlights how crucial reproductive counseling is for breast cancer survivors. Researchers found that almost two-thirds of breast cancer survivors in the study weren’t using birth control despite not wanting to get pregnant. Unfortunately, this puts survivors at an increased risk of an unplanned pregnancy. Unplanned pregnancies are problematic because many breast cancer survivors take endocrine therapy, such as tamoxifen, for five years or longer to prevent a recurrence. These medications can be harmful to a developing fetus.

Hormone-free contraceptives appear to be the safest choice for most breast cancer survivors and are what health care professionals typically recommend. Effective nonhormonal contraceptive options include:

Copper intrauterine devices. Paragard is an intrauterine device (IUD) that offers long-term birth control (up to 10 years) for premenopausal women. The device is a T-shaped plastic frame that’s inserted into the uterus. It is 99% effective at preventing pregnancy. Copper wire coiled around the device produces an inflammatory reaction toxic to sperm and eggs, thus preventing pregnancy.
Double barrier method. This uses two forms of contraception: either a condom, female condom or diaphragm in conjunction with nonprescription spermicides such as nonoxynol-9 or a prescription vaginal contraceptive gel such as Phexxi. This method is 75% to 80% effective at preventing pregnancy.
Natural family planning. Natural family planning is a method of birth control that helps you predict when ovulation will happen based on observation of fertility indicators. It typically involves charting your temperature daily, tracking changes in cervical mucus and paying attention to other key fertility signs. This method is 75% to 80% effective at preventing pregnancy.
Sterilization. In women, you may have heard this referred to as tubal sterilization or “getting your tubes tied.” In men, it’s called a vasectomy. These surgical procedures stop eggs or sperm from traveling and are reserved for people who don’t want children or are done having children. They’re 99% effective at preventing pregnancy.

Not as much is known about how hormonal methods of contraception — available in intrauterine devices, injectables and pills — may influence the risk of cancer progression or relapse in survivors. Hormonal birth control contains a combination of estrogen and progestin or progestin only that can encourage cancer growth.

Because of uncertainty regarding safety, health care professionals typically recommend that people with hormone receptor-positive breast cancer avoid these types of contraception.

In those who’ve had hormone receptor-negative breast cancer or a noninvasive form of breast cancer (ductal carcinoma in situ), hormonal birth control may be an option, but this is considered on a case-by-case basis and only after a thorough discussion about the risks and benefits with members of their health care team.

Do ovarian suppression drugs work as birth control?

The short answer is no. Ovarian suppression drugs, also referred to as GnRH analogs, are sometimes prescribed as adjuvant endocrine therapy for premenopausal women with hormone receptor-positive breast cancer. Examples include leuprolide (Lupron) or goserelin (Zoladex). The goal in this case is to temporarily shut down the ovaries to decrease the level of estrogen in the body and reduce the risk of the cancer recurring. (These drugs can also be used to preserve fertility during cancer treatment.)

You might think that if you’re taking medicine to shut down your ovaries — which

stops menstruation in most women — that you wouldn’t need birth control. But ovarian function may not be completely suppressed in some people, making pregnancy a possibility.

So don’t assume you can’t get pregnant if you’re taking a GnRH analog. Talk to your primary care doctor about finding a nonhormonal contraceptive that works for you.

Can I get pregnant after breast cancer treatment?

While there’s no way to know for sure whether a successful pregnancy in an individual breast cancer survivor is possible, many women do get pregnant and deliver healthy babies after treatment. And it’s not uncommon to conceive naturally. At the same time, multiple factors influence the likelihood of a successful pregnancy, including:

Your age.
The treatment you received (chemotherapy is known to lower the number of eggs a woman has).
The protective measures used during treatment, such as temporarily suppressing ovarian function with medications such as leuprolide (Lupron) or goserelin (Zoladex).
Your fertility status before treatment.
The health of the sperm involved.
The quantity and quality of your remaining eggs, also known as ovarian reserve.
The frequency of your attempts to conceive.

Whether you used a fertility preservation technique before cancer treatment is also a factor. Preservation options include the following: freezing of your eggs, also called oocyte cryopreservation, for future fertilization and implantation; freezing an egg that’s been fertilized by a partner or donor sperm, called embryo cryopreservation, for future implantation; or a procedure that involves removing part of, or the entire ovary for freezing. This last option is known as ovarian tissue cryopreservation. These procedures are performed before or during treatment and offer another way to get pregnant.

The risk of ovarian damage depends heavily on the type of cancer treatment received. For example, certain types of chemotherapy drugs can cause more damage than other kinds of treatment. A small study of breast cancer survivors who had undergone chemo- therapy treatment found that up to three-quarters of the participants had their ovarian function return. However, this didn’t guarantee the ability to get pregnant. Blood tests and imaging, such as ultrasound, can help your provider determine if your egg supply, or ovarian reserve, is healthy.

When is it safe to get pregnant after breast cancer treatment?

Safely timing a pregnancy depends on many factors, whether you’ve had cancer or not. Fortunately, there doesn’t appear to be an increased risk of cancer recurrence if conception happens soon after treatment ends, even among hormone receptor-positive breast cancer breast cancer survivors. Breastfeeding doesn’t appear to raise the risk of recurrence either.

And recent studies suggest that getting pregnant within two years of treatment isn’t harmful to the mother or baby, although there may be an increased risk of certain pregnancy complications, discussed in the next section.

If you’re considering pregnancy, talk with your OB-GYN, oncologist or other members of your health care team. If you’re on adjuvant endocrine therapy, you’ll need to stop taking it and wait to conceive until the medication clears your system, since it can be harmful to a developing baby.

The good news here is that taking a break from endocrine therapy to have a baby does not increase the risk of cancer returning, according to a recent study of conception and pregnancy in young women who had early-stage hormone receptor-positive breast cancer. In addition, most of the women in the trial became pregnant and delivered healthy babies as desired — encouraging results for young breast cancer survivors who wish to start a family.

Will my past breast cancer treatment affect my pregnancy and baby?

As in any pregnancy, prenatal care is critical to a healthy pregnancy and delivery. But there are some additional concerns for breast cancer survivors. On average, these pregnancies tend to result in infants with lower birth weight, smaller sizes for gestational age, greater likelihood of preterm delivery and greater chance of being delivered by Cesarean section.

Overall, though, most babies born to people who have undergone breast cancer treatment are healthy. They have no greater likelihood of genetic defects or postpartum health problems than those born without a maternal history of breast cancer. One exception is this: if you have a specific genetic mutation that increases cancer risk. In this case, your child has a 50% chance of inheriting this mutation. A genetic counselor can help you understand these hereditary risks. Ask your primary care doctor or oncologist for a referral if you need one.