Is a mammogram (mammo) safe during pregnancy?

Mammography Safety During Pregnancy

Mammography is safe during pregnancy, with the fetal radiation dose from a 4-view mammogram being less than 0.03 mGy, well below the 50 mGy threshold where teratogenic effects might occur. 1

Safety Profile of Mammography in Pregnancy

• Mammography is not contraindicated during pregnancy, and the National Comprehensive Cancer Network guidelines confirm that mammography with abdominal shielding can be performed safely 1
• No teratogenic effects have been demonstrated at radiation doses below 50 mGy, making the <0.03 mGy exposure from mammography negligible to fetal development 1
• Lead shielding should be utilized for pregnant patients undergoing mammographic imaging to further minimize any potential radiation exposure 1

Imaging Algorithm for Pregnant Women

For Pregnant Women with Palpable Masses:

• Ultrasound should be the first-line imaging modality for pregnant women with palpable masses due to its:

  • Highest sensitivity (100% in many studies) for diagnosis of pregnancy-associated breast cancer 1
  • Ability to characterize benign etiologies without radiation exposure 1
  • Effectiveness in young women with dense breast tissue 1, 2

• Mammography should be used as a second-line or adjunct imaging tool when:

  • Ultrasound is negative but clinical suspicion remains 1
  • Ultrasound shows suspicious findings requiring further characterization 1
  • There is a need to evaluate for microcalcifications or architectural distortion that may be sonographically occult 1

For Pregnant Women with Nipple Discharge:

• Diagnostic mammograms with retroareolar magnification views may be beneficial as initial examination or as an adjunct to ultrasound in pregnant women with persistent nipple discharge 1
• Ultrasound techniques such as peripheral compression, 2-handed compression, and rolled nipple technique can help detect causes of bloody nipple discharge 1

Diagnostic Performance in Pregnancy

• Mammography has slightly decreased sensitivity (74-90%) compared to ultrasound in pregnant women, primarily due to increased breast density 1
• More recent studies using full-field digital technique have reported improved sensitivity of up to 100% for mammography during pregnancy 1, 3
• The combined use of mammography and ultrasound provides a very high negative predictive value (>97%) when both are negative or benign 4, 3

Common Pitfalls to Avoid

• Delaying imaging evaluation of breast symptoms in pregnant women can lead to delayed diagnosis and potentially poorer outcomes 2, 5
• Relying solely on clinical examination is insufficient, as physiologic changes of pregnancy may mask signs of disease 5, 6
• Assuming that all breast masses during pregnancy are benign can lead to missed diagnoses, as pregnancy-associated breast cancer can present with seemingly benign features 1, 7
• Avoiding mammography due to unfounded radiation concerns may result in incomplete evaluation, particularly for microcalcifications that are better visualized on mammography than ultrasound 6, 3

Digital Breast Tomosynthesis (DBT) Considerations

• While there are no specific studies evaluating DBT in pregnant women, this technology may be beneficial due to:
  • Improved visualization of breast masses in dense tissue 1
  • Decreased masking effect of dense breast tissue that is common in younger and pregnant women 1
  • Ability to better characterize lesions that might be obscured on standard mammography 1