Pregnancy after breast cancer safe, should be discussed earlier in cancer care

A review of studies looking at pregnancy after breast cancer found that, while a history of breast cancer is associated with low birth weight and small size during pregnancy, getting pregnant after breast cancer is safe and not associated with birth defects in the child.

The study, presented on Thursday during the San Antonio Breast Cancer Symposium, found that women with a history of breast cancer are less likely than women with a history of any other cancer, except cervical cancer, to get pregnant after treatment ends. It also found that for those who do go on to carry pregnancies, the outcomes are similar to women with no history of cancer.

Background

Breast cancer primarily affects women, and some common breast cancer treatments can affect the ability to get pregnant. For young women who still want to have children, or who have not yet decided if they want children, the possibility of losing your fertility is another way that a breast cancer diagnosis can upend your life.

Few women conceive after breast cancer, and many people worry about the safety of getting pregnant after chemotherapy or hormonal therapy.

The study

This study brought together previous research on three major issues in pregnancy after breast cancer compared to pregnancies in the general population:

• How often do women become pregnant after a breast cancer diagnosis?
• What are the outcomes of those pregnancies?
• What are the health effects on the woman after those pregnancies?

The study found that women who have been treated for breast cancer are much less likely to get pregnant than the general population. They are also less likely to become pregnant than women who have been treated for other cancers, cervical cancer being the one exception.

The study found some effects on the outcomes of pregnancies. Women who had a history of breast cancer, compared to the general population, were more likely to have pregnancies with:

• cesarean section deliveries
• preterm births
• low birth weights
• fetuses small for their age in the womb

When looking more closely at the data, researchers found that these effects were seen primarily in women who got chemotherapy.

Pregnancies in women previously treated for breast cancer were no different than pregnancies in the general population in their chances of ending in miscarriage, being aborted, or resulting in ongoing medical conditions in the child.

Pregnancies did not affect breast cancer outcomes or the overall risk of dying for women with a history of breast cancer. Compared to other women with breast cancer, women who got pregnant were not more likely to have cancer return or to die of any cause.

What this means for you

This study provides important information for women who may have concerns about getting pregnant after a breast cancer diagnosis. The few pregnancy concerns that were more likely after a breast cancer diagnosis are not permanent and can be managed through close communication with your doctor.

One issue that remains the subject of ongoing research is the effect of taking a break from hormonal therapy, which can continue for 5 to 10 years after active treatment, to get pregnant. The POSITIVE trial is actively looking at this question now, but if you are on hormonal therapy and want to try to get pregnant, you should speak to your medical team about doing so safely. Let them know about your wishes and concerns you may have about waiting until the end of hormonal therapy to try to get pregnant.

This study also found that many women will not get pregnant after breast cancer treatment. For many this is a choice. However, some women may want to get pregnant but, as a side effect of treatment, may not be able. The presenters did not suggest why pregnancy rates after breast cancer are lower than they are in the general population, but said these results should encourage healthcare providers to provide fertility counseling at diagnosis.

It is important that newly diagnosed women are informed about the effect treatment can have on fertility and actions they can take before treatment starts to protect their ability to have a biological child. If you are newly diagnosed, speak to your doctor as soon as you can and ask them to refer you to a fertility specialist.

Healthcare providers should provide reassurance about the safety of pregnancy after breast cancer when discussing survivorship. For women who may still be able to be pregnant after breast cancer treatment, and who are interested in doing so, you should feel comfortable knowing that data shows pregnancy is safe for you and the baby.