Pregnancy After Breast Cancer
Considering Fertility
For many young adults with breast cancer, one of the most personal challenges is the desire to have a biological child in the future. In fact, about 50% of young breast cancer patients report concerns about fertility. If you’re facing similar questions, shared decision-making between you and your doctor is crucial, allowing you to balance fertility preservation and family-building goals with an effective treatment plan.
Timing Considerations
Your decision around pregnancy after treatment may be shaped by your individual breast cancer risk. Some people delay pregnancy to complete treatment to lower the chances of cancer returning. Others feel ready to try sooner. There’s no one-size-fits-all answer. Talk with your oncologist and, if possible, a fertility specialist to explore your options. Together, you can make a plan that reflects your goals, cancer type, treatment needs, recurrence risk, and the impact of time on fertility.
If you have early-stage, hormone-receptor-positive breast cancer, figuring out the right timing for pregnancy can be especially complex. Pregnancy-related hormones were once believed to raise the risk of recurrence, but extensive research has shown that’s not the case. Still, endocrine (hormone) therapies like tamoxifen, aromatase inhibitors, or ovarian suppression medications are often prescribed for 5–10 years after diagnosis to help prevent recurrence. These medications can make pregnancy unsafe or impossible during that time. And because fertility declines with age, waiting to finish hormone therapy may make it harder to conceive later.
The POSITIVE Trial
Some people may choose to pause endocrine therapy to pursue pregnancy. Researchers at Dana-Farber and other institutions studied the safety of this by launching the POSITIVE trial (Pregnancy Outcome and Safety of Interrupting Therapy for Women With Endocrine-ResponsIVE Breast Cancer). It’s the first prospective study to track the safety of pausing endocrine therapy to try for pregnancy.
This study demonstrated that taking a two year pause from endocrine therapy to pursue pregnancy, after completing at least 18 months, is safe from a disease recurrence perspective. Further follow-up data is needed to confirm long-term safety. Learn more about POSITIVE.
Safety Considerations
Is it safe for me to become pregnant after breast cancer?
Yes. Research has found that pregnancy after breast cancer does not increase the risk of recurrence or worsen your prognosis. This holds true for both estrogen receptor positive (ER+) and estrogen receptor negative (ER–) breast cancers, as well as for people with BRCA1 or BRCA2. That said, there is still a risk of recurrence during or after pregnancy, so staying in close contact with your care team is essential.
Is it safe for my future child if I become pregnant after breast cancer?
Yes. Having had breast cancer doesn’t raise the risk of birth defects in your future child(ren)—but some cancer medications can cause damage to the fetus. Some drugs may take longer to clear from your body, so it’s important to follow the specific timing recommended by your healthcare team.
It’s strongly recommended to avoid getting pregnant while undergoing chemotherapy or hormonal therapy (like Tamoxifen), as these treatments can cause serious birth defects, especially in the first trimester. Other cancer treatments may also be dangerous during pregnancy. Use contraception while undergoing treatment, and talk with your doctor about the options that are best for you.
In the below video, Ann Partridge, MD, MPH, founder and director of Young and Strong, discusses pregnancy after breast cancer with a panel of other specialists and patients in the Young and Strong Program
