Breast Cancer During Pregnancy: Treatment, Risks, and Breast Feeding

Pregnancy comes with a lot of surprisessome adorable (tiny hiccups!), some less so (heartburn that could power a small furnace).
A breast cancer diagnosis during pregnancy lands firmly in the “nobody ordered this” category. The good news: in many cases, breast
cancer can be treated during pregnancy, and many people go on to deliver healthy babies while still getting effective cancer care.

This article breaks down what treatment typically looks like, what risks matter most (and which fears are common but not always accurate),
and how breastfeeding fits into the plan. We’ll keep it evidence-based, practical, and humanbecause you deserve more than vague reassurance
and a pamphlet that reads like it was written by a robot with no feelings.

What “breast cancer during pregnancy” really means

Doctors often use the term pregnancy-associated breast cancer (PABC) for breast cancer diagnosed during pregnancy (and sometimes
in the postpartum period). It’s uncommon, but it’s being seen more often as more people have children later in their 30s and 40sages when
breast cancer risk is naturally higher.

The core challenge isn’t that pregnancy makes breast cancer “untreatable.” The challenge is timing: you’re treating one patient (you)
while protecting another (the baby). That means some therapies are safe during certain trimesters, while others are usually delayed until after delivery.

Signs and symptoms that deserve a second look

Pregnancy changes breast tissuemore fullness, tenderness, and lumpiness can feel “normal.” That’s exactly why persistent changes should be checked
instead of politely ignored.

• A new lump that doesn’t go away after 1–2 weeks
• Thickening or a firm area that feels different from the surrounding tissue
• Skin changes (dimpling, redness that doesn’t resolve, “orange peel” texture)
• Nipple changes (new inversion, persistent crusting, bloody discharge)
• One-sided swelling or rapid size change that seems out of proportion

If you’re thinking, “But pregnancy already does half of that,” you’re not wrong. The key is persistence, asymmetry, and anything that feels truly new.
You’re not being dramaticyou’re being appropriately suspicious. (A+ life skill, honestly.)

How doctors diagnose breast cancer during pregnancy

Imaging: what’s safe?

Most workups start with breast ultrasound. It doesn’t use ionizing radiation and is excellent for evaluating lumps in dense or hormonally
active breast tissue.

Mammography can also be performed when needed, typically with abdominal shielding. Because pregnancy and lactation make breasts denser,
mammograms can be harder to interpretbut they can still provide useful information, especially for calcifications.

MRI may be considered in select situations. Pregnancy is a special case: providers are cautious about contrast agents, and decisions are
individualized. The big idea is that imaging choices are made to get the information needed for treatment while minimizing fetal exposure.

Biopsy: yes, you canand usually should

If imaging looks suspicious, a core needle biopsy is typically recommended. This is important: pregnancy is not a reason to “wait and see”
when cancer is on the list of possibilities. A biopsy provides a diagnosis and helps determine the tumor’s biology (like hormone receptor status), which
directly influences treatment options.

Staging and treatment goals: two priorities, one plan

Staging evaluates tumor size, lymph node involvement, and whether cancer has spread. During pregnancy, the care team also considers what tests are
necessary and which can be postponed or replaced with safer alternatives.

Treatment goals are usually the same as in non-pregnant patients:
treat the cancer effectively, avoid delays that could worsen outcomes, and protect long-term health.
The difference is sequencingwhat happens now versus postpartum.

Treatment options by trimester

Here’s the simplified “big picture” (your actual plan will depend on cancer stage, tumor type, and how far along the pregnancy is).

Surgery: lumpectomy vs. mastectomy

Surgery is commonly the first treatment during pregnancy. Both lumpectomy (breast-conserving surgery) and mastectomy may be options.
The decision often comes down to what additional treatment is needed afterward.

Here’s the practical twist: lumpectomy is usually paired with radiation therapy. Since radiation is typically postponed until after delivery,
some pregnant patients choose mastectomy to reduce the need for immediate radiation. Others have lumpectomy and plan radiation postpartum.
There isn’t one “right” choicethere’s the choice that fits your cancer and your timeline.

Breast reconstruction is often delayed until after delivery to avoid extra anesthesia time and reduce surgical complexity during pregnancy.
(Your body is already doing a major construction projectadding a renovation is optional.)

Lymph node evaluation and sentinel lymph node biopsy

Lymph nodes matter because they help guide staging and treatment. In non-pregnant care, sentinel lymph node biopsy is common. During pregnancy,
approaches vary by center and situation. Some techniques are used cautiously, and your team will weigh benefits and fetal exposure considerations.
If you hear words like “mapping,” “tracer,” or “sentinel node,” it’s normal to ask for a plain-English explanation of what’s being used and why.

Chemotherapy: when it’s used and why timing matters

Chemotherapy is usually avoided in the first trimester because early fetal organ development occurs then. Starting in the
second trimester, certain chemotherapy regimens may be used when the benefit to the mother is significant.

In the second and third trimesters, many patients who need chemotherapy can receive it with careful monitoring. Your oncology team will choose drugs
and schedules that are commonly used in pregnancy when treatment cannot safely wait. This is one reason pregnancy-associated breast cancer care is best
handled by a multidisciplinary team that includes oncology and maternal-fetal medicine.

Timing matters near delivery, too. Teams often avoid giving chemotherapy too close to the due date to reduce the risk of low blood counts or infection
complications around labor and postpartum recovery. Translation: they’re not just thinking about the baby’s safetythey’re also thinking about
your safety during one of the most physically demanding weeks of your life.

Radiation therapy: usually a “postpartum plan”

Radiation can pose fetal risk, so it’s generally postponed until after delivery. If radiation is an important part of treatment (often after lumpectomy),
your team will map out how to sequence surgery, possible chemotherapy, delivery timing, and postpartum radiation so cancer care stays on track.

Hormone therapy and targeted therapy: typically delayed

Some breast cancers are fueled by hormones (estrogen and/or progesterone). In those cases, medications like tamoxifen (or aromatase inhibitors in other
contexts) may be part of treatmentbut they’re generally not used during pregnancy.

For HER2-positive breast cancer, targeted therapies like trastuzumab are extremely important in non-pregnant treatment. During pregnancy, however,
these drugs are typically delayed because of known fetal risks (including serious effects on amniotic fluid in reported cases). The care team may focus
on surgery and pregnancy-compatible chemotherapy first, then start HER2-targeted therapy after delivery.

Immunotherapy and newer agents

Some newer treatments (including certain immunotherapies) have limited pregnancy safety data. In practice, that usually means they’re avoided during
pregnancy unless there’s a compelling reason and specialists agree on a risk-benefit approach. If your tumor is triple-negative and immunotherapy is being
discussed, expect a very personalized conversation.

Risks during pregnancy: what to watch, what to expect

Risks to the baby

The main fetal risks depend on treatment type and gestational age. In general:

• First trimester chemotherapy is associated with higher risk of fetal malformations and is usually avoided.
• Second/third trimester chemotherapy has been used with fewer congenital malformations reported, but careful monitoring is essential.
• Prematurity is one of the most common issuesoften related to planned early delivery to allow postpartum treatment.

Many specialists try hard to avoid early delivery unless it’s truly necessary, because prematurity itself can carry health risks. A frequent goal is:
treat effectively during pregnancy when possible, then deliver as close to term as is safely achievable.

Risks to the mother

The biggest maternal risk isn’t pregnancy itselfit’s delay. Pregnancy can mask symptoms, and people may postpone evaluation because they
assume breast changes are “just pregnancy stuff.” Earlier diagnosis generally means more options and better outcomes.

Treatment side effects can also stack onto pregnancy symptoms. Nausea, fatigue, and anemia can happen in pregnancy; chemotherapy can intensify them.
That’s why supportive care (nutrition, anti-nausea strategies, mental health support, and obstetric monitoring) matters as much as the cancer drugs.

Does pregnancy worsen breast cancer prognosis?

This question is loaded with fear, and understandably so. The reassuring reality is that when breast cancer during pregnancy is compared with similar
cancers in non-pregnant patients of the same age and stage, outcomes can be similar. The key driver of prognosis is usually the stage and tumor biologynot
the fact that you’re pregnant.

The take-home message: pregnancy doesn’t automatically mean “worse cancer,” but it can make diagnosis later if symptoms are dismissed. So the best
strategy is not panicit’s prompt evaluation and coordinated care.

Breast feeding: what’s possible, what’s not, and what’s “it depends”

Breastfeeding questions deserve clear answersbecause “maybe?” is not a feeding plan at 3 a.m.

Can you breastfeed while receiving cancer treatment?

In most cases, breastfeeding is not recommended during chemotherapy because many anticancer drugs can pass into breast milk and may harm
the baby. The same caution applies to many hormone therapies and targeted therapies. If postpartum treatment needs to start soon, your team may recommend
not starting breastfeeding or stopping before therapy begins.

Can you breastfeed between delivery and starting treatment?

Sometimes. If there’s a window after delivery before certain treatments begin, some patients may breastfeed briefly. This depends on your treatment schedule,
surgical recovery, and which medications are planned. The safest approach is to ask for medication-specific guidance rather than relying on general rules.

Breastfeeding after surgery

Breastfeeding after lumpectomy or mastectomy depends on what was done and which breast(s) can still produce milk. A mastectomy removes the milk-producing
tissue on that side, so breastfeeding from that breast won’t be possible. With lumpectomy, milk production may be reduced depending on how much tissue and
how many ducts were affected.

Many people can breastfeed from the unaffected breast, and some can partially breastfeed (with supplementation) depending on supply. Working with a lactation
consultant earlyideally before deliverycan make a big difference.

Breastfeeding after radiation

Radiation can reduce milk production in the treated breast and may change the skin and ducts, making breastfeeding more difficult on that side. Some people
still produce some milk; others don’t. Again, one-breast feeding is a real option for many families.

If you can’t breastfeed (or choose not to), you’re not failing

When cancer treatment is urgent, feeding decisions can feel painfully unfair. If stopping breastfeeding is necessary, your team may discuss strategies to
manage engorgement and discomfort and connect you with postpartum support. Your baby needs you healthy. That’s not a sloganit’s the whole point.

A practical timeline example (because real life runs on calendars)

Here’s a simplified example of how care might be sequenced. This is not a templatejust a realistic illustration of how timing decisions work.

Example scenario

Patient: 34 years old, 20 weeks pregnant, newly diagnosed with stage II breast cancer. Tumor testing shows aggressive features and lymph node
involvement, so chemotherapy is recommended.

1. Week 20–22: Surgery to remove the tumor and evaluate lymph nodes (or in some cases, chemo first if recommended).
2. Week 24–34: Pregnancy-compatible chemotherapy regimen with close obstetric monitoring.
3. Late pregnancy: Stop chemotherapy with enough buffer time before delivery to reduce infection/bleeding risk.
4. Delivery: Aim for as close to term as possible if both mother and baby are stable.
5. Postpartum: Begin radiation (if needed), hormone therapy (if hormone receptor–positive), and/or targeted therapy (if HER2-positive).
6. Feeding plan: Depending on postpartum treatment urgency, breastfeeding may be avoided or limited; formula and/or donor milk may be discussed.

The pattern is consistent: treat effectively during pregnancy with what’s safe, then “activate” the full menu of therapies postpartum.

Questions to ask your care team (bring this liststeal it proudly)

• What type of breast cancer do I have (hormone receptor status, HER2 status), and how does that change treatment?
• What treatments are safe during my trimester, and which ones should wait until after delivery?
• Is surgery recommended now, and what type (lumpectomy vs. mastectomy) makes sense given postpartum radiation timing?
• If chemotherapy is recommended, when would it start and stop relative to delivery?
• Will treatment affect my delivery plan (timing, location, NICU availability)?
• Can I breastfeed at alland if not, what’s the safest plan for feeding and managing milk suppression?
• Can I meet with a lactation consultant and a maternal-fetal medicine specialist early?
• What support resources are available for mental health and practical help (transportation, childcare, financial counseling)?

Experiences that many families describe (and what they wish they’d known) 500+ words

There’s the medical plan, and then there’s the lived experiencethe part that doesn’t fit neatly into a treatment protocol. Many people describe the
first week after diagnosis as emotionally disorienting: you’re still thinking about baby names and anatomy scans, and suddenly you’re learning new words
like “staging,” “receptor status,” and “multidisciplinary tumor board.” It can feel like switching channels mid-show without the remote.

One common theme is the frustration of being told, early on, that a lump is “probably hormonal.” Some patients share that they had to pushpolitely or not
for an ultrasound or a biopsy. Looking back, they often say the same thing: “I’m glad I insisted.” Self-advocacy can feel awkward, especially when you’re
used to trusting your body’s changes as normal pregnancy changes. But pregnancy is not a medical invisibility cloak. If something feels off, you deserve a
thorough evaluation.

Another frequent experience is the weird emotional collision of feeling the baby move during cancer care. People describe sitting in an infusion chair,
hand on belly, feeling kicks while nurses check vitals. The moment can feel surrealcomforting and heartbreaking at the same time. Some say it helped them
tolerate treatment: every kick was a reminder of why they were doing the hard thing. Others felt angry that their pregnancy wasn’t the joyful season they
expected. Both reactions are normal, and neither one makes you “less grateful.”

Many families also talk about the practical grind: appointments multiply fast. There’s oncology, obstetrics, maternal-fetal medicine, imaging, labs,
sometimes genetics counseling, sometimes surgery consultsyour calendar starts to look like a medical conference schedule. People often wish they’d named
a “logistics captain” early (partner, sibling, friend) to handle phone calls, childcare, rides, and meal trains. Not because you can’t do it, but because
you shouldn’t have to do it alone.

Breastfeeding can become the most emotionally loaded “small” decision. Some patients hoped breastfeeding would be the one part of pregnancy they could
controlonly to learn they’d need to stop quickly to begin postpartum treatment. Others couldn’t breastfeed because of surgery, low supply, or medication
safety concerns. People often describe grieving the loss of that plan, even while understanding the medical necessity. If you’re in that position, it can
help to reframe feeding as a spectrum: some breast milk, donor milk, formula, combination feedingthese are all legitimate ways to nourish a baby. Your bond
is built through care, not through a single method of nutrition delivery.

On the hopeful side, many survivors describe a powerful sense of perspective after delivery: the baby arrives, treatment continues, and life becomes a series
of doable steps rather than a single overwhelming mountain. People often say they underestimated how much support existsoncology social workers, lactation
consultants, peer mentor networks, postpartum mental health specialists, and other parents who’ve been through it. Connecting with someone who has navigated
breast cancer during pregnancy can turn “terrifying unknown” into “hard but possible.”

If there’s one piece of wisdom that shows up repeatedly, it’s this: ask for the plan in writing. When your brain is tired (and pregnancy brain is already
a full-time job), written timelines, medication lists, and “what happens next” steps are a lifeline. Clear information doesn’t erase fear, but it makes fear
smallerand it gives you something solid to hold onto.

Conclusion

Breast cancer during pregnancy is complexbut it’s not automatically catastrophic, and it’s not automatically a choice between your health and your baby’s.
Many treatments (especially surgery and carefully selected chemotherapy in later trimesters) can be used during pregnancy. Other therapies, like radiation,
hormone therapy, and most targeted therapies, are commonly postponed until after delivery. The biggest advantage you can give yourself is timely evaluation
and a coordinated team that treats both oncology and pregnancy as top priorities.

Breastfeeding decisions are deeply personal, and sometimes they’re constrained by medication safety and treatment urgency. If breastfeeding can’t happenor
can’t happen the way you imaginedit does not diminish your parenthood. Your job is to get through treatment and keep showing up. And you can do that.

Medical note: This article is for educational purposes and is not a substitute for individualized medical advice. Always consult your oncology and obstetric care team for guidance tailored to your situation.