Screening Mammography During Breastfeeding
Yes, screening mammography can and should be performed in lactating women when indicated based on age and risk factors, though the woman should breastfeed or pump immediately before the examination to minimize breast density and optimize sensitivity. 1
Key Recommendations by Risk Category
Average-Risk Women Age 40 and Older
- Continue routine screening mammography during lactation according to standard ACR screening guidelines 1
- Breastfeeding is NOT a contraindication to screening
- The decision should factor in the underlying risk level and expected duration of lactation 1
High-Risk Women (Including BRCA Carriers)
- Screening should continue during lactation regardless of age, as some pregnancy-associated breast cancers have been detected only through screening mammography in high-risk lactating women 1
- Evidence shows 7.7% of pregnancy-associated breast cancers were subclinical, with 5 cases detected only by screening mammography 1
Average-Risk Women Under Age 40
- Screening is generally not recommended during lactation unless other high-risk factors are present 1
Critical Pre-Examination Strategy
Have the patient breastfeed or pump immediately before the mammogram to:
- Minimize breast density from milk distention
- Optimize mammographic sensitivity
- Reduce false-positive findings 1
This simple intervention addresses the primary limitation of screening during lactation—the physiologically increased mammographic density that occurs when lobules are distended with milk 1.
Understanding the Limitations
Reduced Sensitivity
Lactation causes variable increases in mammographic density, which can mask small lesions 1. Despite this limitation:
- Some cancers are only detectable by mammography (particularly those presenting as microcalcifications)
- The increased risk of biologically aggressive breast cancer in the postpartum period may outweigh the reduced sensitivity 2
Increased False-Positives
Lactating women have higher rates of:
However, given that pregnancy-associated breast cancers tend to be more aggressive and present at advanced stages, the benefits of screening likely outweigh these risks 1.
Supplemental Imaging Considerations
Digital Breast Tomosynthesis (DBT)
While no studies specifically evaluate DBT during lactation, it may theoretically benefit this population by decreasing the masking effect of dense breast tissue 1. Consider DBT if available, particularly in high-risk women.
Breast MRI for High-Risk Screening
- MRI during lactation shows marked background parenchymal enhancement (82% of cases) 3
- Specificity is reduced to 60% with only 2% positive predictive value 3
- Despite limitations, MRI screening remains relevant for high-risk patients (such as BRCA carriers) during lactation 3
- Consider waiting 3 months after cessation of lactation for optimal MRI performance if timing permits 1
Common Pitfalls to Avoid
Delaying screening "until after breastfeeding": This can result in delayed cancer diagnosis. Some women breastfeed for extended periods (1-2+ years), creating unacceptable gaps in surveillance 1
Assuming all masses are benign lactational changes: While 80% of biopsied palpable masses in lactating women are benign, pregnancy-associated breast cancers do occur and can have deceptively benign imaging features 1
Forgetting to have the patient empty the breasts first: This single intervention significantly improves examination quality 1
Safety Considerations
Mammography during lactation is completely safe:
- No radiation exposure to the infant through breast milk
- Standard radiation dose to breast tissue (no special modifications needed)
- No need to "pump and dump" after the examination
The evidence consistently supports that screening should not be deferred solely because a woman is breastfeeding, particularly when she meets age-based or risk-based screening criteria 1, 4.