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Fertility and Future Pregnancy

Reviewed by: Elizabeth S. Ginsburg, MD

Updated October 18, 2012

If you are young and premenopausal (still having menstrual periods), breast cancer treatments can affect your fertility. This may make it harder for you to become pregnant after treatment ends.

You might not be thinking about family planning at the time of your diagnosis. Yet that’s the best time to  talk with your healthcare team about future fertility. If you’re already in treatment or beyond, you can still discuss your options now with your providers.

How Treatments Affect Fertility

Of all breast cancer treatments, chemotherapy is most likely to affect your fertility. Chemotherapy can damage follicles, the egg-containing sacs, in the ovaries. This reduces the number of eggs and shortens the amount of time you will be fertile if your periods return.

Chemotherapy may cause your period to stop temporarily or permanently because of the loss of eggs in your ovaries.

  • To save your eggs for future use, you may harvest them before starting chemotherapy.
  • When periods return, they almost always do so within a year after chemotherapy.

Long-term effects depend on the type of chemotherapy, dose and your age.

  • Chemotherapy that contains cyclophosphamide (Cytoxan) has the strongest chance of causing infertility.
  • High-dose treatment with medicines known as alkylating agents is more likely to cause infertility than low-dose.
  • Doxorubicin (Adriamycin) and cisplatin (Platinol) cause infertility at a moderate rate.

Women under age 40 rarely lose all eggs. If all eggs are lost, your periods will not return. This is called premature ovarian failure, or premature or early menopause.

Doctors usually advise waiting at least two years after chemotherapy before trying to get pregnant. This allows the medicine to leave your body, and to make sure the cancer has not returned. (If you are pregnant and recently diagnosed, visit our section on Pregnant with Breast Cancer.)

Hormonal therapy such as tamoxifen may cause your periods to become irregular or stop. Even though you might not ovulate (release eggs, which leads to menstrual periods) while on tamoxifen, you could still be fertile.

  • Use barrier birth control such as a diaphragm or condoms while taking tamoxifen because it can damage a fetus.

Tamoxifen’s greatest effect on your fertility may come from the time delay caused by the recommended five years of treatment. The older you are, the harder it is to become pregnant. Adding five years may push you into menopause, especially if you have also had chemotherapy.

Some women seek to shorten their tamoxifen regimen to two or three years to increase their pregnancy chances. Research shows tamoxifen is most effective when given for five years, so talk with your provider about your specific situation.

Many doctors advise waiting three months after tamoxifen treatment ends before trying to become pregnant.

Surgery that removes the ovaries, called oophorectomy, immediately ends your fertility. Used to lower estrogen levels, oophorectomy puts you into permanent menopause. Lumpectomy and mastectomy do not affect your fertility.

Targeted (biologic) therapy such as trastuzumab (Herceptin) does not appear to affect fertility but more research is needed to understand its effects. Because we have so little information, you should not become pregnant while on targeted therapy. Doctors advise waiting six months after treatment ends before trying to become pregnant.

Radiation to the breast does not harm fertility.

Fertility and Age

Your age is important in predicting your chances for fertility and pregnancy after breast cancer treatment.

  • If you are younger than 30, you are likely to ovulate and be fertile.
  • Between the ages of 30 and 35, you have a good chance for fertility.
  • Fertility declines after age 35. At 40 or older, you are more likely to be infertile. Age reduces the number and quality of eggs in the ovaries. Treatment takes an added toll. Older eggs have more trouble forming healthy embryos, attaching to the uterus and resulting in pregnancy.

If you  freeze your eggs or embryos before treatment, your age when the eggs are removed is their “age” when you use them. So eggs taken when you are 32 and re-implanted when you are 38 are still eggs from a 32-year-old.

Preserving Fertility, Timing Treatment

Assisted reproductive technology may help you become pregnant after breast cancer treatment.

Before starting breast cancer treatment, consult with a fertility specialist, a doctor called a reproductive endocrinologist, who is experienced in treating women affected by breast cancer. Some methods are:

Harvesting eggs

The best time to take eggs from your ovaries for future use is before treatment begins, even if you don’t know whether you want a child later. You do not need a partner to harvest and freeze your eggs.

Natural menstrual cycles produce one or two eggs. Fertility medicines given for about two weeks increase that number.

  • Women diagnosed with breast cancer usually have one cycle of egg stimulation. This is believed likely to be safe, but more and larger studies are needed.
  • Your doctor may give you tamoxifen, an aromatase inhibitor, or both during the egg-stimulating cycle, to lower potential exposure of your breasts to estrogen.

Freezing eggs and embryos

Eggs are removed in an outpatient procedure. They may be frozen without being fertilized, or fertilized in a lab with sperm from your partner or a sperm donor. Then they are grown to form embryos. The eggs and embryos are frozen for use after breast cancer treatment.

  • Embryo freezing is the most common method; this process takes two to six weeks.
  • Ovarian tissue freezing is possible, but is considered very experimental. 

Fertility procedures often are coordinated with breast cancer treatment, usually during the weeks between surgery and chemotherapy.Talk to your oncologist and fertility specialist about timing.      

Determining Fertility After Treatment

If you haven’t had your period for one year after treatment ends, there is about a 10 percent chance your periods will start again.

But having periods or menopausal symptoms is not a reliable sign of whether you are fertile. The most reliable test for fertility is trying to become pregnant. Some tests that may help determine if you have a reduced number of eggs in your ovaries include:

  • FSH (follicle-stimulating hormone) level
  • AMH (anti-mullerian hormone) level
  • Inhibin b hormonal level
  • Ultrasound of ovaries

It may take up to six months after you finish treatment to get accurate readings.

Many factors unrelated to breast cancer treatment can also affect your fertility, such as blocked fallopian tubes, uterine fibroids, sperm problems in your partner and other issues that any woman could have. Talk about any and all concerns with your doctor.

Pregnancy Post-treatment

Pregnancy after breast cancer treatment does not raise your risk of cancer returning or affect your survival, studies show. Because treatment can sometimes damage the heart or lungs, your doctor should check them before you become pregnant.  

Even if you are now menopausal, you can have frozen eggs or embryos implanted and carry a pregnancy. A gestational carrier can also carry the pregnancy for you. If you did not freeze eggs or embryos and are in premature menopause, you can still have a baby using donor eggs.

Adoption offers another route to parenthood, whether you are single or partnered. Many adoption agencies are open to those with cancer histories.Some agencies might have a waiting period, or time after treatment, or require a letter from your oncologist. Sharing your complete medical history is standard for all prospective adoptive parents.    

Talking with Your Team About Fertility 

You may not know if you want to have a child or children after treatment, but taking steps now can help you keep your options open.

As early as you can — before breast cancer treatment begins, if possible — tell your oncologist about your interest in becoming pregnant after treatment ends. Also meet with a reproductive endocrinologist to discuss your family planning options.

Consider asking these questions, along with others that may be important to you:

  • What is my prognosis (outlook for future impact of breast cancer) and any ongoing treatment I might need?
  • How will the recommended breast cancer treatment affect my fertility?
  • Can I postpone treatment long enough (two to six weeks) to have my eggs extracted for future use? Can this be done between my scheduled surgery and the start of chemotherapy?
  • What fertility preservation methods might help me?
  • What are the chances at my age that I will be able to become pregnant after breast cancer treatment?
  • If I’ve already had some treatment, what can I do to help my fertility?
  • What are my options if I go into permanent menopause?
  • How much will assisted reproduction (fertility) procedures cost?

Resources on Fertility

Fertile Hope, a LIVESTRONG initiative providing reproductive information, support and hope to those whose cancer treatments present the risk of infertility. Financial assistance program., a resource from the Oncofertility Consortium at Northwestern University. Information on cancer treatment and fertility-sparing options; operates National Fertility Hotline at (866) 708-3378 to answer questions, connect with programs nationwide. 

Society for Reproductive Endocrinology and Infertility, to find fertility specialists. 

This article was supported by Cooperative Agreement Number DP11-1111 from The Centers for Disease Control and Prevention. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention.