Breast Imaging

Breast Cancer Screening in Pregnancy: What Imaging Is Best for High-Risk Patients Over 25?

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Breast Cancer Screening in Pregnancy: What Imaging Is Best for High-Risk Patients Over 25?

A 28-year-old patient, G1P0 at 14 weeks gestation, is in your office for a routine prenatal visit. She is anxious about her breast cancer risk, noting her mother was diagnosed at age 42. As a high-risk individual, she would typically be undergoing annual screening, but she is concerned about the safety and appropriateness of imaging during her pregnancy. You face the critical decision of how to balance her elevated personal risk with the safety of the fetus, navigating the physiologic breast changes of pregnancy that can complicate interpretation. This article provides a clinical workflow for this exact scenario: breast cancer screening in a pregnant female, age 25 or older, with higher-than-average risk. According to the American College of Radiology (ACR) Appropriateness Criteria, the recommended study, Digital breast tomosynthesis screening, is rated Usually Appropriate.

Who Fits This Clinical Scenario for Breast Cancer Screening During Pregnancy?

This guidance applies specifically to pregnant patients who are 25 years of age or older and are considered to have a higher-than-average risk for breast cancer. This risk category is typically defined by established guidelines and may include individuals with:

  • A known pathogenic or likely pathogenic mutation in a breast cancer susceptibility gene (e.g., BRCA1, BRCA2).
  • A lifetime risk of 20% or greater, calculated using risk assessment models that account for family history.
  • A history of radiation therapy to the chest between the ages of 10 and 30.
  • A strong family history, such as a first-degree relative with premenopausal breast cancer.

This workflow is for screening in an asymptomatic, high-risk patient. It is crucial to distinguish this from a diagnostic workup. This guidance does not apply to patients presenting with new clinical signs or symptoms.

  • Exclusion 1: Palpable Mass or Focal Pain. If the patient has a new palpable lump, focal pain, or skin changes, the clinical question shifts from screening to diagnosis. This presentation follows a different workflow, detailed in the ACR variant for a Pregnant female with a focal pain or palpable breast mass.
  • Exclusion 2: Suspicious Nipple Discharge. A patient with spontaneous, bloody, or serosanguinous nipple discharge also requires a diagnostic, not screening, evaluation.
  • Exclusion 3: Average-Risk Patients. For pregnant individuals at average risk, routine screening mammography is typically deferred until after delivery.

What Diagnoses Are You Working Up in This Screening Scenario?

Screening aims to detect malignancy at its earliest, most treatable stage. In a high-risk pregnant patient, the physiologic changes of pregnancy—including increased glandular density and vascularity—can create a challenging background. The primary goal is to differentiate benign, pregnancy-related changes from potential pathology.

Pregnancy-Associated Breast Cancer (PABC) This is the central concern. PABC refers to breast cancer diagnosed during pregnancy, lactation, or within one year postpartum. It is an uncommon but consequential diagnosis, as PABC often presents at a more advanced stage due to both diagnostic delays and potentially more aggressive tumor biology. Effective screening in the high-risk population is intended to mitigate this risk of delayed diagnosis.

Ductal Carcinoma In Situ (DCIS) DCIS is a non-invasive, stage 0 breast cancer where abnormal cells are confined to the milk ducts. It is a frequent target of screening mammography, often appearing as suspicious microcalcifications. Detecting DCIS is a primary goal, as it can progress to invasive cancer if left untreated.

Invasive Ductal or Lobular Carcinoma The ultimate goal of screening is to identify invasive cancers before they become clinically apparent. Early detection significantly improves prognosis and allows for less aggressive treatment options, which is particularly important when coordinating care around pregnancy and delivery.

Benign Physiologic Changes Increased hormonal stimulation during pregnancy leads to significant changes in breast tissue. Conditions like lactational adenomas, galactoceles, and simple fibroadenomas can develop or grow, sometimes mimicking malignancy on imaging. A successful screening examination must be able to distinguish these expected findings from suspicious lesions requiring further workup.

Why Is Digital Breast Tomosynthesis the Recommended Screening for This Patient?

For a high-risk pregnant patient over 25, both Digital breast tomosynthesis (DBT) screening and standard 2D Mammography screening are rated Usually Appropriate by the ACR. However, DBT is often preferred in this setting due to its distinct advantages in dense breast tissue.

Pregnancy and lactation induce increased glandular density, which can obscure underlying lesions on a standard 2D mammogram. DBT, also known as 3D mammography, acquires images from multiple angles to create a series of thin slices. This technique reduces the effect of overlapping tissue, which can improve cancer detection rates and, importantly, decrease the rate of false positives and unnecessary patient recalls for additional imaging.

Radiation and Fetal Safety The primary concern for any imaging during pregnancy is radiation exposure to the fetus. For both DBT and standard mammography, the radiation dose to the breast is low (☢☢ 0.1-1 mSv), and the dose to the fetus is negligible when proper abdominal shielding is used. The scattered radiation dose to the fetus is estimated to be less than 0.01 mGy, which is far below the 50 mGy threshold associated with deterministic effects. Therefore, a single screening mammogram with appropriate shielding is considered safe at any point during gestation.

Rationale for Lower-Rated Alternatives

  • MRI breast without and with IV contrast is rated Usually not appropriate for screening. While breast MRI is the most sensitive screening tool for high-risk patients in the non-pregnant state, its use during pregnancy is limited. The primary reason is the use of gadolinium-based contrast agents, which are known to cross the placenta and enter fetal circulation. While no definitive harm has been proven in humans, the long-term effects are unknown, and its use is reserved for specific diagnostic situations where the benefits clearly outweigh the theoretical risks.
  • US breast is rated May be appropriate. Breast ultrasound is an invaluable tool for diagnostic workups (e.g., evaluating a palpable lump) and involves no ionizing radiation. However, as a primary screening modality for the entire breast, it has limitations. It is less sensitive than mammography for detecting microcalcifications, a key sign of DCIS, and its effectiveness is highly dependent on the operator. It is best used as a supplemental tool for a targeted evaluation after an abnormal mammogram.

For detailed technical parameters on performing this study, including patient positioning and shielding, refer to our comprehensive guide on the Screening Mammography (with DBT) protocol.

What’s the Next Step After Screening Mammography in a Pregnant Patient?

The results of the screening mammogram, reported using the Breast Imaging Reporting and Data System (BI-RADS) classification, will dictate the subsequent workflow.

  • Negative or Benign Finding (BI-RADS 1 or 2): This is a reassuring result. The patient can continue with their routine high-risk surveillance schedule, with the next imaging study typically planned for the postpartum period according to established guidelines.
  • Incomplete Finding (BI-RADS 0): This is a common outcome, especially given the increased breast density of pregnancy. It indicates that more imaging is needed for a complete evaluation. The standard next step is a diagnostic workup, which typically involves diagnostic mammographic views (e.g., spot compression, magnification) and a targeted breast ultrasound of the area of concern.
  • Suspicious Finding (BI-RADS 4 or 5): If a finding is suspicious for malignancy, a tissue diagnosis is required. The preferred method is an ultrasound-guided core needle biopsy. This procedure is safe during pregnancy, as it uses local anesthesia, avoids radiation, and provides a definitive histologic diagnosis to guide management.
  • Probably Benign Finding (BI-RADS 3): A BI-RADS 3 classification presents a unique challenge in pregnant patients. In non-pregnant individuals, this typically prompts short-interval follow-up imaging (e.g., in 6 months). During pregnancy, this approach may be modified. A multidisciplinary discussion involving the radiologist, obstetrician, and surgeon is crucial to decide between short-interval follow-up (often with ultrasound) or proceeding directly to biopsy to avoid any diagnostic delay.

Pitfalls to Avoid (and When to Get Help)

Navigating breast imaging in this scenario requires careful consideration to avoid common errors.

  • Pitfall 1: Deferring Screening Due to Pregnancy. In a high-risk patient, the risk of delaying a cancer diagnosis can outweigh the minimal risk of radiation from a shielded mammogram. Do not automatically postpone necessary screening.
  • Pitfall 2: Ordering a Contrast-Enhanced Study for Screening. Gadolinium-based contrast for MRI is contraindicated for routine screening during pregnancy. Reserve it for very specific, high-stakes diagnostic dilemmas after consultation with a radiologist.
  • Pitfall 3: Inadequate Clinical History. Failing to provide the radiologist with the patient’s specific risk factors, gestational age, and the reason for the exam (screening vs. diagnostic) can lead to a suboptimal interpretation or protocol.
  • Pitfall 4: Misinterpreting Physiologic Changes. The radiologist must be experienced in interpreting images from pregnant and lactating patients to avoid mistaking benign changes like a galactocele for a suspicious mass.

If a suspicious finding is identified (BI-RADS 4 or 5), immediate escalation for a multidisciplinary consultation with breast surgery, medical oncology, and maternal-fetal medicine is essential to coordinate biopsy and subsequent management.

Related ACR Topics and Tools

This article covers a single, specific clinical scenario. For a broader view of all related presentations or to explore the underlying data, the following resources are available.

Frequently Asked Questions

Is it safe to perform a mammogram at any trimester of pregnancy?

Yes. With proper abdominal and pelvic lead shielding, the radiation dose to the fetus from a screening mammogram is negligible and well below the threshold for concern. The American College of Radiology and the American College of Obstetricians and Gynecologists consider mammography to be safe at any point during pregnancy when clinically indicated.

Why is digital breast tomosynthesis (DBT) preferred over standard 2D mammography for this scenario?

While both are rated ‘Usually Appropriate,’ DBT is often preferred because it reduces the effect of overlapping tissue. Pregnancy causes increased breast density, which can hide cancers on a 2D mammogram. DBT’s 3D-like reconstruction improves cancer detection and reduces the chance that a patient will be called back for extra pictures due to benign, overlapping tissue.

If a patient is high-risk due to a BRCA mutation, should I order an MRI instead?

No, not for routine screening during pregnancy. While MRI is the standard of care for screening BRCA carriers in the non-pregnant state, it is rated ‘Usually not appropriate’ for screening during pregnancy. This is due to the need for gadolinium-based contrast, which is avoided because it crosses the placenta. Shielded mammography is the recommended screening modality.

What if the patient is under 25 but still high-risk?

That is a distinct clinical scenario. While the principles are similar, the risk-benefit analysis for radiation exposure in very young patients may be considered differently. The ACR addresses this in a separate variant for high-risk pregnant females under age 25, and consultation with a breast imaging specialist is recommended.

If the mammogram is negative, does the patient need any other imaging before delivery?

Generally, no. A negative screening mammogram (BI-RADS 1 or 2) is reassuring. The patient should be advised to remain vigilant with clinical self-exams and can typically resume her standard high-risk screening protocol (which may include MRI) after she has finished breastfeeding.

Reviewed by Pouyan Golshani, MD, Interventional Radiologist — May 30, 2026