Medical Oncologist
CION Cancer Clinics
Breastfeeding and hereditary breast cancer risk | CION Cancer Clinics
Breastfeeding does not appear to raise breast cancer risk in women who carry a gene fault, and it may lower it a little, especially with BRCA1. It does not replace screening. This page explains what the evidence shows, how feeding fits around scans, surgery and cancer medicines, and what to do about a lump that appears while you are feeding. At CION Cancer Clinics, our team helps carriers and their families plan checks, next steps and support after a genetic result.
NG
Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
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On this page
- Does breastfeeding lower breast cancer risk if you carry a gene fault?
- What does breastfeeding mean in your situation?
- How do screening and breastfeeding fit together?
- The terms that come up, in plain language
- Breastfeeding before and after preventive surgery
- What this page cannot tell you
- Four things carriers are told about breastfeeding
- Common questions about breastfeeding and gene faults
The short answer
Does breastfeeding lower breast cancer risk if you carry a gene fault?
It may lower it a little, and it does not appear to raise it. In women generally, breastfeeding is linked with a slightly lower risk of breast cancer. In women with a BRCA1 fault, several studies suggest a similar small benefit. For BRCA2 and other genes, the evidence is less clear.
What the evidence can and cannot say
The studies so far compare women who chose to breastfeed with women who did not. They cannot fully separate breastfeeding from everything else that differs between those groups. The benefit, where it shows up, is modest. It is a reason to breastfeed if you want to, not a reason to feel guilty if you cannot.
Why it does not replace your plan
For a carrier, the things that make the biggest difference are regular screening and, for some women, surgery to lower risk. Breastfeeding sits alongside those. It does not take their place, and it is not a reason to delay a scan or skip an appointment. Think of it as one helpful habit within a plan your team has already built around you, rather than a plan in itself.
Breastfeeding cannot pass a gene fault to your baby. Genes are inherited at conception, not through milk.Where you are now
What does breastfeeding mean in your situation?
The answer depends less on the gene and more on what has already happened to your breasts, and what medicines you are taking.
You have not had breast surgery
Breastfeed as you and your baby wish. Your screening continues, with some changes to how and when scans are done while you are feeding.
You are thinking about preventive mastectomy
Removing the breast tissue also removes the tissue that makes milk. Many women choose to finish having and feeding their children before surgery. It is one option among several, and the timing is a conversation with your surgeon and counsellor together.
You have been treated for breast cancer
After surgery and radiotherapy to one breast, that side often makes less milk. The other breast usually works normally, and many women feed from one side.
Worth asking your team
- Whether the treated side can be used at all
- How a new lump will be checked while feeding
- When screening of the other breast is due
You are taking cancer medicines
Most cancer medicines, including hormone tablets and chemotherapy, pass into breast milk. Breastfeeding is usually stopped during treatment. Never restart or stop a medicine on your own to allow feeding.
Not sure whether this applies to you?
Ask an oncologistKeeping watch while feeding
How do screening and breastfeeding fit together?
Tell your screening team you are feeding
A feeding breast looks different on a scan. The radiologist needs to know, so the images are read against the right picture of normal.
Expect screening to continue
Feeding changes which test is used and when, but it rarely means screening stops. Your team will set the timing, as explained on our page on surveillance in pregnancy.
Feed or express just before the scan
Emptier breasts are more comfortable to scan and easier to read. Ask whether the appointment can be timed around a feed.
Know which lumps are common
Blocked ducts, milk-filled cysts and breast infections are all common while feeding. They usually settle with feeding, warmth and, for an infection, treatment from your doctor.
Get any lump that does not settle checked
As a carrier, do not wait until you stop feeding. A lump that stays, grows or feels different from the rest should be seen by your breast team promptly.
Words you will meet
The terms that come up, in plain language
- BRCA1 and BRCA2
- The two genes most often behind inherited breast cancer. A fault in either one raises breast and ovarian cancer risk.
- Carrier
- Someone who has an inherited gene fault but does not have cancer. A carrier is not a patient and does not need treatment.
- Risk-reducing mastectomy
- Surgery to remove healthy breast tissue to lower future risk. It ends the ability to breastfeed from that breast.
- Mastitis
- An inflamed, painful breast during feeding, sometimes with infection and fever. It is common and treatable.
- Galactocele
- A cyst filled with milk. It is a harmless and common cause of a lump while breastfeeding.
- Breast MRI
- A scan using magnets rather than X-rays, often used to screen carriers. A feeding breast can look busier on it.
Side by side
Breastfeeding before and after preventive surgery
Before risk-reducing mastectomy
After risk-reducing mastectomy
Breastfeeding is possible as usual
Breastfeeding is no longer possible
Breast screening continues, adjusted while feeding
Your surgeon reviews what checks you still need
Lumps during feeding need a prompt check
New lumps near the scar still need a check
The timing of surgery is still open
Babies are fed with formula or donated milk
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Being straight with you
What this page cannot tell you
It cannot tell you how much breastfeeding would change your own risk. That depends on your gene, your age, your family history and the rest of your plan. What your specific result means is a question for the counsellor who ordered the test.
It cannot set the timing of surgery for you
Whether to wait until you have finished having and feeding children before preventive surgery is a balance between your risk and your plans for a family. Your surgeon and counsellor can help you weigh it, and our page on timing pregnancy around surgery goes further.
Who this does not apply to
If you cannot breastfeed, or choose not to, you have not added to your risk in any way that matters next to screening. Formula feeding is a safe choice, and nobody should make you feel otherwise. Male carriers, and women without a known gene fault, will find the general advice for their situation more useful than this page.
Your baby's wellbeing and your own come first. The effect of breastfeeding on your risk is small by comparison.Commonly believed
Four things carriers are told about breastfeeding
"Breastfeeding can pass the gene fault to my baby."
It cannot. Your baby either inherited the fault at conception or did not. Nothing in breast milk changes a child's genes.
"If I breastfeed long enough, I will not need screening."
Any benefit from breastfeeding is modest. It does not bring a carrier's risk down to that of other women, so your screening plan stays in place whether or not you feed.
"Carriers should not breastfeed because the hormones feed cancer."
There is no good evidence that breastfeeding raises risk in carriers. The studies that exist point, if anything, the other way, particularly for BRCA1.
"After reconstruction, I can breastfeed from the new breast."
A reconstructed breast has no milk-producing tissue. It can look and feel like a breast, but it cannot make milk. This is worth knowing before you decide on the timing of surgery.
Questions we are asked
Common questions about breastfeeding and gene faults
Is it safe for a BRCA carrier to breastfeed?
Yes. There is no good evidence that breastfeeding raises cancer risk in carriers, and it may lower it slightly. Keep up your screening while you feed, and tell the radiologist you are feeding so your scans are read correctly.
How long should I breastfeed to lower my risk?
Nobody can give you a figure that applies to you. In studies of women generally, a longer total time spent breastfeeding across all children was linked with more benefit. Feed for as long as works for you and your baby, rather than to hit a target.
Can I have a breast MRI while breastfeeding?
Usually, yes, although your team may change the timing. Feeding or expressing just before the scan helps. Ask the radiology team what they advise about feeding after the contrast dye, as practice varies between centres.
I found a lump while breastfeeding. Should I worry?
Most lumps during feeding are blocked ducts, milk-filled cysts or infection. As a carrier, though, get any lump that does not settle checked by your breast team promptly. Do not wait until you have stopped feeding.
Can I breastfeed after breast-conserving surgery and radiotherapy?
Often from the untreated breast, which usually works normally. The treated side tends to make less milk, and some women find it makes none. Your breast team and a lactation adviser can help you plan feeding from one side.
Can I breastfeed while taking tamoxifen or having chemotherapy?
Generally not. Most cancer medicines pass into milk and could reach the baby. Your oncologist will advise when it is safe to feed again after treatment ends. Do not change your medicines yourself to allow breastfeeding.
Should I delay preventive mastectomy until I finish breastfeeding?
Many women choose to, and many do not. It depends on your risk, your age and how many children you hope to have. Screening continues while you wait. Your surgeon and counsellor can help you weigh the timing together.
Who can advise me on breastfeeding as a carrier?
Your genetic counsellor, your breast team and a lactation adviser each cover a part of it. Call the CION helpline if you are not sure where to start, and someone will point you to the right clinic. Counselling in Telugu can be arranged.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
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Sources
- National Cancer Institute — Genetics of Breast and Gynecologic Cancers (PDQ) - Health Professional Version
- National Cancer Institute — Breast Cancer Prevention (PDQ) - Patient Version
- National Cancer Institute — BRCA Gene Changes: Cancer Risk and Genetic Testing Fact Sheet
- GeneReviews (NCBI) — BRCA1/2 Hereditary Breast and Ovarian Cancer
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Timing pregnancy around risk-reducing surgeryIf you are weighing surgery against a family still to comeTiming pregnancy around cancer treatmentWhen feeding and treatment overlapFamily planning with a cancer geneThe wider picture for carriers planning childrenFertility preservation for carriersKeeping options open before surgery or treatment
Talk to us
Planning a family as a carrier?
A counsellor can help you plan screening, feeding and the timing of any surgery around the family you want. One helpline serves every CION centre.