A RadioGraphics review (1 October 2026) brings together the American College of Radiology Appropriateness Criteria and other society guidance on breast screening and diagnosis in pregnant and lactating women.
Mammography is safe in pregnancy and lactation, but hormonal changes raise density and lower sensitivity. Ultrasound uses no ionising radiation and is the first test for a symptomatic woman, though its role in routine screening is uncertain. Contrast-enhanced MRI is avoided in pregnancy but can be used during lactation for high-risk screening or staging, despite marked background enhancement.
Pregnancy-associated breast cancer is rising as childbearing is delayed, and it is often diagnosed late because symptoms are put down to pregnancy. A lump in a pregnant or breastfeeding woman deserves the same prompt imaging as in anyone else.
- Image any persistent breast lump in pregnancy or lactation promptly, starting with ultrasound.
- Add mammography when ultrasound is suspicious or a malignancy is found; the review describes it as safe in pregnancy.
- Avoid gadolinium-enhanced breast MRI in pregnancy; it can be used during lactation.
- Do not stop high-risk screening during lactation; ask the woman to feed or express just before mammography.
- Do not attribute a new mass to pregnancy without imaging.
Why it matters
Delay, not the imaging, is the main hazard for women with pregnancy-associated breast cancer.
Read the rest in the app
You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.
Scan to keep reading on your phone. No account needed to start.
Tomorrow morning, before your first patient
One edition a day for radiology, written by the desk, every claim tied to its paper. Six minutes.
Get the app — free