Pregnancy After Breast Cancer: What Partners Should Know
For many young adults diagnosed with breast cancer, one of the most personal challenges is the desire to have a biological child in the future. About 50% of young breast cancer patients report concerns about fertility. As a partner, you play a key role in supporting informed decisions, especially when it comes to balancing family-building hopes with treatment plans designed to reduce cancer risk and, when possible, support future pregnancy.
Timing Considerations
The decision to try for pregnancy after breast cancer treatment is deeply personal and often influenced by a patient’s individual cancer risk. Some may choose to delay pregnancy in order to finish treatment or reduce the chance of recurrence. Others may feel ready to try sooner. There’s no one-size-fits-all answer. Encouraging your partner to speak with their oncologist—and, if appropriate, a fertility specialist—can help clarify options. Together, you can create a plan that reflects your goals, your partner’s cancer type, their treatment needs, and how time may impact fertility.
If your partner has early-stage, hormone-receptor-positive breast cancer, planning the timing of pregnancy can be especially complex. While pregnancy-related hormones were once thought to increase the risk of recurrence, research has shown this is not the case. However, endocrine (hormonal) therapies such as Tamoxifen, Aromatase Inhibitors, or ovarian suppression medications are often prescribed for 5–10 years after treatment to prevent recurrence. These medications can make pregnancy unsafe or impossible during that time. And because fertility declines with age, waiting to finish therapy may make it harder to conceive later.
To study this more closely, researchers at Dana-Farber and other institutions launched the POSITIVE trial (Pregnancy Outcome and Safety of Interrupting Therapy for Women With Endocrine-ResponsIVE Breast Cancer). It’s the first prospective study to examine the safety of pausing endocrine therapy to try for pregnancy. You can read more on the POSITVE study here.
Safety Considerations
Is it safe for my partner to become pregnant after breast cancer?
Yes, research shows it is. Studies have found that becoming pregnant after breast cancer does not increase the risk of recurrence or worsen prognosis. This is true for both estrogen receptor positive (ER+) and estrogen receptor negative (ER–) breast cancers, and for individuals with BRCA1 or BRCA2 mutations/pathogenic variants.
A recent study also found no increased recurrence risk among people with ER+ breast cancer who paused endocrine therapy like Tamoxifen, Lupron, or Aromatase Inhibitors in order to try for pregnancy. That said, breast cancer can still come back during or after pregnancy, so staying in close contact with the care team is important.
Is it safe for our future child if my partner becomes pregnant after breast cancer?
Yes. A history of breast cancer does not increase the risk of birth defects, as long as medications have fully cleared the body. This typically requires a waiting period of at least 3 months before trying to conceive, although some drugs, like Herceptin, may require a longer break. It’s essential to follow guidance from your partner’s medical team on timing.
It’s strongly recommended that pregnancy be avoided during chemotherapy and endocrine therapy (like Tamoxifen), as these treatments can cause serious birth defects, especially in the first trimester. Some other cancer treatments may also be unsafe during pregnancy. Make sure to use effective contraception throughout treatment, and speak with the care team about the safest options. Learn more about contraception.
Genetic Considerations
If you and your partner are thinking about having children, family history may also play a role in the decision. Some people carry inherited gene mutations—like BRCA1 or BRCA2—that can raise the risk of passing cancer on to their children. If this is a concern for your partner, one option to consider is preimplantation genetic diagnosis (PGD).
With PGD, your partner would undergo in vitro fertilization (IVF) to collect eggs, which are then fertilized to create embryos. The embryos are tested to identify which carry the gene mutation and which do not. If your partner chooses, only embryos without the mutation can be implanted.
Starting or growing a family after breast cancer is a personal decision, and your support matters. Talking together with your partner’s care team can help you both feel informed and supported as you explore your options.
Breastfeeding After Breast Cancer
After diagnosis and treatment, your partner may hope to grow your family, and possibly breastfeed. The good news? Research shows that breastfeeding is both safe and possible after breast cancer.
To learn about how different treatments may affect breastfeeding and the experiences of other breast cancer survivors, visit the Breastfeeding After Breast Cancer page.
How You Can Support Your Partner
Breastfeeding after breast cancer can bring up a lot of emotions. Encouraging your partner to connect with healthcare providers, including lactation specialists, can be helpful at any stage: before, during, or after pregnancy. Mental health support, like talk therapy, can also make a big difference. You’re not just a bystander, you’re part of the care team.
