Ensuring Pregnant and Lactating People Get the Breast Cancer Screenings They Need
Safety and efficacy are key concerns when choosing the right imaging methods
In concert with the RadioGraphics monograph, RSNA News shares the latest on the role of medical imaging in disease screening.
Uncertainty about the safety of breast imaging during pregnancy and lactation can create confusion for patients and referring providers. The issue is particularly relevant as more women require breast cancer screening during their reproductive years, including those with elevated genetic risk who may need to begin screening at a younger age.
“As more women delay pregnancy until later in life, radiologists are seeing an increasing number of women who need breast cancer screening during pregnancy and lactation,” said Haydee Ojeda-Fournier, MD, FACR, FSBI, the Grillo-Marxuach Endowed Medical Director of Breast Imaging at UC San Diego Health in La Jolla, CA, and senior author of a recent RadioGraphics article on the subject.
“Add to this the uncertainties and misinformation about imaging safety during pregnancy and lactation, and we have identified a group of patients for whom we need to raise awareness,” she asserted. “We also need to educate primary care providers and empower radiologists with evidence-based information.”
A Closer Look at Screening Modalities
Mammography remains an option for screening during pregnancy and lactation, according to Dr. Ojeda-Fournier. “Breast cancer screening with digital mammography, including full-field digital mammography or digital breast tomosynthesis, can be safely performed throughout pregnancy and lactation, with reported cancer detection sensitivity rates of 74% to 100%,” she and her colleagues wrote.
“For mammography, even when units operate at their maximum output dose for multiple views, the total uterine dose remains extremely low (0.16 mGy, far below the 50-mGy threshold for deterministic or stochastic fetal effects),” she added. “The actual fetal dose is even lower due to attenuation by the uterus.”
Mammographic changes related to lactation. (A, B) Bilateral mediolateral oblique mammograms obtained during lactation in a 40-year-old woman show heterogeneously dense breasts (Breast Imaging Reporting and Data System [BI-RADS] density category C) with increased overall volume and a diffuse increase in parenchymal density related to physiologic lactational changes. (C, D) Bilateral mediolateral oblique mammograms obtained when the same patient was aged 38 years and was not breastfeeding also show heterogeneously dense breast tissue, but with smaller breast size and lower overall parenchymal density compared with the images acquired during the lactating state.
https://doi.org/10.1148/rg.260005 ©RSNA 2026
Despite its safety, breast screening during pregnancy and lactation remains challenging. “The breast undergoes physiologic changes that can mimic malignancy, both clinically and by imaging,” Dr. Ojeda-Fournier said.
Dense breast tissue may obscure mammographic findings, and marked parenchymal enhancement during lactation can limit visualization on MRI.
Although contrast-enhanced breast MRI is appropriate for lactating patients, it is contraindicated during pregnancy, Dr. Ojeda-Fournier noted.
US presents a different set of considerations. While it is an excellent diagnostic tool for evaluating symptoms such as a palpable mass, she noted that it is a much less effective screening test.
“Ultrasound has higher false-positive rates, leads to more unnecessary biopsies and there is very limited evidence supporting its use as a stand-alone screening examination in pregnant or lactating women,” she explained.
When imaging findings require further evaluation, image-guided breast interventions are safe during both pregnancy and lactation, Dr. Ojeda-Fournier emphasized.
“The risk of milk fistula is very low and manageable,” she said. “Biopsy should not be postponed because a patient is pregnant or lactating, as the risk of missing a pregnancy-associated breast cancer can be catastrophic.”
Existing Guidance and the Need for More Data
Of all the issues related to breast cancer screening in this patient population, Dr. Ojeda-Fournier considers the greatest challenge to be the lack of evidence.
“Pregnant and lactating women have been excluded from randomized clinical trials, and it is unlikely that they will ever be included,” she said. “Thus, radiologists have to rely on observational data, safety principles and expert consensus when making screening recommendations in this group of patients.”
Radiologists can consult the 2025 American College of Radiology Appropriateness Criteria regarding imaging decisions for pregnant patients. They can also refer to guidelines from other professional organizations, such as the National Comprehensive Cancer Network.
The goal is not to perform all imaging modalities in each patient, but to choose the right modality based on age and risk factors, Dr. Ojeda-Fournier asserted. She also emphasized the importance of effective radiologist-patient communication.
“Patients frequently express anxiety about radiation exposure and potential fetal or neonatal harm,” Dr. Ojeda-Fournier said.
She advises against using overly technical radiation dose language, which can confuse patients. “Even a well-intentioned comparison of fetal radiation dose to the annual background radiation dose can be misinterpreted or difficult to contextualize,” she noted.
“The radiologist's role is to provide clear, evidence-based information about the safety and limitations of screening during pregnancy and lactation, and to help select the safest, most effective modality to prevent delays in breast cancer diagnosis,” Dr. Ojeda-Fournier concluded.
For More Information
Access the RadioGraphics article, “Breast Cancer Screening in Pregnant and Lactating Patients: A Practical Approach,” and the related commentary, “Importance of Breast Cancer Screening in Pregnant and Lactating Patients.”
Read previous RSNA News stories on breast cancer screening: