Fertility and Breast Cancer

August 31, 2015
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If you are young and premenopausalinfo-icon (still having menstrual periods), breast cancer treatments can affect your fertilityinfo-icon. 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 diagnosisinfo-icon. 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

Chemotherapyinfo-icon can affect your fertilityinfo-icon by damaging follicles, the egg-containing sacs, in the ovaries. This treatment lowers the number of eggs and shortens the amount of time you’ll be fertile if your periods return after treatment.

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.

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

In 2015, research came out showing that for young women with hormone receptorinfo-icon-negative breast cancer, taking medicineinfo-icon to temporarily shut down the ovaries (goserelininfo-icon) with chemotherapy increased the chance of having a baby after treatment. Because the study is small, using this class of medicine for fertility preservation remains controversial.

Long-term effects depend on the type of chemotherapy, doseinfo-icon and your age:

Some doctors advise waiting 6 months after chemotherapy before trying to get pregnant. Others advise waiting as long as 2 to 10 years. This allows the medicine to leave your body, and to make sure the cancer has not returned. If you are pregnant and recently diagnosed, learn about being pregnant with breast cancer.

Hormonal therapyinfo-icon such as tamoxifeninfo-icon may cause your periods to become irregular or stop. Even though you might not ovulate, or release eggs and have a menstrual periodinfo-icon, while on tamoxifen, you could still be fertile.

  • Use the long-acting reversible contraceptive copper IUD or barrier birth control such as a diaphragm or condoms while taking tamoxifen, because tamoxifen can harm a fetus.

Tamoxifen’s greatest effect on your fertility may come from the time delay caused by the recommended 5 to 10 years of treatment. The older you are, the harder it is to become pregnant. Adding 5 to 10 years may push you into menopauseinfo-icon, especially if you have also had chemotherapy.

Some women seek to shorten their tamoxifen regimeninfo-icon to 2 or 3 years to increase their pregnancy chances. Research shows tamoxifen is most effective when given for 5 to 10 years, so talk with your provider about your specific situation.

Doctors advise waiting at least 2 months after tamoxifen treatment ends before trying to become pregnant.

Surgeryinfo-icon that removes the ovaries, called oophorectomyinfo-icon, immediately ends your fertility and puts you into permanent menopause. Lumpectomyinfo-icon and mastectomyinfo-icon don’t affect your fertility.

Targeted therapyinfo-icon such as trastuzumabinfo-icon (Herceptininfo-icon) does not appear to affect fertility but more research is needed to understand its effects. You should not become pregnant while on targeted therapy because it can harm a fetus. Doctors advise waiting 6 months after treatment ends before trying to become pregnant.

Radiationinfo-icon to the breast does not harm fertility.

Fertility and Age

Your age is important in predicting your chances for fertilityinfo-icon and pregnancy after breast cancer treatment. In women who have been treated with chemotherapyinfo-icon or had their ovaries removed:

  • If you are younger than 30, you’re likely to ovulate and be fertile.
  • Between the ages of 30 and 35, you have a good chance of being fertile.
  • Fertility declines after age 35. At 40 or older, you are more likely to be infertileinfo-icon.
  • Age reduces the number and quality of eggs in the ovaries. Treatment can further reduce that number. Older eggs have more trouble forming healthy embryos that are needed to become pregnant.

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’re 38 are still eggs from a 32-year-old.

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