Radiologic examinations in pregnancy: a critical appraisal of radiation and contrast risks

Radiologic examinations (medical imaging studies involving ionizing radiation) are sometimes avoided in pregnancy due to concerns about maternal and fetal radiation exposure. However, diagnostic imaging can be critical for maternal and fetal care, and the actual risks are frequently overestimated.

To provide a critical appraisal of radiation and contrast exposure during pregnancy, focusing on fetal dosage from commonly used imaging modalities, associated risks, and clinical contexts in which radiologic studies may be appropriate.

A narrative review of the literature was performed, emphasizing guideline statements from professional societies, large cohort and case-control studies, and updated dosimetric data.

Across X-ray, computed tomography, nuclear medicine, and fluoroscopic examinations, fetal radiation exposure is typically far below the 50-100 mGy threshold associated with teratogenicity. Most diagnostic studies deliver fetal doses under 25 mGy, a level at which adverse outcomes have not been demonstrated. Deterministic effects such as structural anomalies are not observed at diagnostic dose ranges. Stochastic risks such as childhood cancer appear negligible or, at most, minimally increased. Guidelines consistently advise that medically indicated imaging should not be withheld in pregnancy.

The available evidence supports the safety of diagnostic radiologic studies in pregnancy when clinically indicated. Perceptions of risk often exceed measured fetal exposures by an order of magnitude, leading to underutilization of important diagnostic tools. Improved awareness of true dose thresholds and integration of shared decision-making are essential to ensure that pregnant patients receive appropriate, timely imaging.