Breast Cancer and Pregnancy

Can you get breast cancer while pregnant?

Yes. Breast cancer diagnosed during pregnancy, or within 12 months of giving birth, is called pregnancy-associated breast cancer (PABC). It is uncommon — affecting approximately 1 in 3,000 pregnancies — but it is the most common cancer diagnosed during pregnancy. Because normal hormonal and physical breast changes in pregnancy can mask a developing tumour, cancers found at this time tend to be diagnosed at a more advanced stage than in non-pregnant women of the same age.

Any new breast lump, change in breast texture, nipple discharge, or skin change that appears during pregnancy or breastfeeding should be reported to your GP or midwife promptly. Do not assume a lump is a cyst or blocked duct without seeking medical assessment.

Diagnosing breast cancer in pregnancy

Diagnosis follows the same triple assessment used outside pregnancy — clinical examination, imaging, and biopsy — but with important modifications:

• Ultrasound is the preferred first-line imaging tool during pregnancy as it does not use ionising radiation.
• Mammography can be performed with abdominal shielding if clinically needed; the dose of radiation reaching the foetus is extremely low.
• MRI without gadolinium contrast is sometimes used to assess extent of disease.
• Core needle biopsy is safe at any stage of pregnancy.
• Staging scans (CT, bone scan) are generally deferred until after delivery if the clinical situation allows, to minimise foetal radiation exposure.

Treatment during pregnancy

Treatment decisions depend on the stage of cancer, gestational age, and the woman's own priorities. Many standard breast cancer treatments can be safely given during pregnancy, with modifications:

Surgery

Surgery — either lumpectomy or mastectomy — is generally safe at any stage of pregnancy and is typically the first-line treatment for pregnancy-associated breast cancer. General anaesthesia carries a small risk and is avoided in the first trimester where possible, but is considered safe from the second trimester onward.

Chemotherapy

Chemotherapy is not recommended in the first trimester (first 12 weeks), when the risk of miscarriage and foetal abnormality is highest. From the second trimester onward, certain chemotherapy regimens (particularly anthracycline-based regimens such as FEC or AC, and taxanes from later in pregnancy) are considered safe for the baby. Long-term studies of children exposed to chemotherapy in the womb have not found significant rates of developmental, cognitive or cardiac problems.

Radiotherapy

Radiotherapy is generally deferred until after delivery, because it cannot be adequately shielded from a growing uterus. In most cases this delay does not worsen outcomes, but the timing and priority of each treatment is decided by your multidisciplinary team.

Hormone therapy and targeted therapy

Hormone therapies (such as tamoxifen) and HER2-targeted treatments (such as trastuzumab/Herceptin) are not given during pregnancy due to known risks to foetal development. These are started after delivery.

Terminating a pregnancy

Current evidence does not show that continuing a pregnancy worsens breast cancer prognosis, nor that terminating a pregnancy improves survival. The decision about whether to continue or end a pregnancy is deeply personal and must be made by the woman in consultation with her medical team. Specialist pregnancy and cancer services can provide the psychological and clinical support needed to make this decision.

Fertility preservation before treatment

For women who are not yet pregnant but require breast cancer treatment that may affect fertility — particularly chemotherapy — fertility preservation options should be discussed before treatment begins. The NHS provides referral to fertility services in this situation. Options include embryo freezing (if there is a partner or donor), egg freezing, and ovarian tissue freezing. Some of these options carry implications for women with hormone receptor-positive breast cancer and should be discussed with a specialist.

Pregnancy after breast cancer treatment

Many women successfully conceive and carry healthy pregnancies after breast cancer treatment. The evidence to date does not suggest that pregnancy after breast cancer increases the risk of the cancer returning. In fact, some studies suggest a lower recurrence risk in women who conceive after treatment, though this may partly reflect selection (women who conceive tend to have had less advanced disease).

• Most oncologists recommend waiting at least 6–24 months after completing treatment before attempting to conceive, to allow the body to recover and to observe for any early signs of recurrence. The timing recommendation varies by individual and cancer type.
• Women on tamoxifen (usually prescribed for 5–10 years) face the most complex timing question. Tamoxifen must not be taken during pregnancy. Pausing tamoxifen to conceive may be considered for some women after 2–3 years of treatment, but this is an active area of clinical guidance and should be discussed with a specialist.
• Women who have had a BRCA mutation identified may also wish to discuss preimplantation genetic diagnosis (PGD) before conceiving.
• Women who experienced chemotherapy-induced early menopause may still have spontaneous fertility or may require fertility treatment.

Breastfeeding after breast cancer treatment

Breastfeeding after breast cancer treatment is possible for many women. If a lumpectomy with radiotherapy has been performed, milk production in the treated breast may be reduced or absent, but the other breast can typically produce sufficient milk. Women who have had a mastectomy can breastfeed from the remaining breast. Breastfeeding is generally not advised while on hormone therapy (tamoxifen) or targeted therapy.

Breastfeeding is beneficial for both mother and baby, and there is no evidence that it increases the risk of breast cancer recurrence. Speak to your oncologist and a lactation specialist for personalised guidance.

Emotional and psychological support

A breast cancer diagnosis during or around pregnancy is one of the most emotionally complex experiences a person can face. Feelings of fear, guilt, grief and uncertainty are all entirely understandable. The NHS provides access to clinical psychology services through breast cancer multidisciplinary teams. Specialist charities including Mummy's Star (UK) provide targeted support for pregnancy-associated breast cancer specifically.