Is a chest X-ray (CXR) safe during pregnancy?

Chest X-Ray is Safe During Pregnancy

Proceed with chest X-ray during pregnancy without hesitation when clinically indicated—the fetal radiation exposure is less than 0.01 mGy, which represents approximately 1/5,000,000th of the established safety threshold for fetal harm (50-100 mGy). 1, 2

Radiation Exposure Context

• A standard chest X-ray delivers less than 0.01 mGy to the fetus, an extraordinarily small dose that falls well below any threshold for concern 1, 2
• The established safety threshold for any detectable fetal harm begins at 50-100 mGy (50,000-100,000 mGy), with no measurable increased risk of prenatal death, malformation, or impaired mental development below this level 3, 1, 2
• The accepted cumulative dose of ionizing radiation during an entire pregnancy is 5 rad (50 mGy), and no single diagnostic chest X-ray approaches this maximum 4

Clinical Decision Framework

The risk of missing a potentially serious maternal diagnosis—such as pneumonia, pulmonary embolism, or other life-threatening conditions—far outweighs the negligible radiation risk from chest X-ray. 3, 1, 2

• Proceed immediately with chest X-ray for acute symptoms including dyspnea, pleuritic chest pain, cough, suspected pneumonia, or suspected pulmonary embolism without delay 1
• Pulmonary embolism remains the leading cause of pregnancy-related maternal death in developed countries, accounting for 20% of maternal deaths in the United States, making timely diagnosis critical 1
• Delaying or avoiding necessary imaging poses greater risk to both mother and fetus than the radiation exposure itself 1, 2

Radiation Protection Technique

• Collimate the X-ray field to the area of interest to minimize any scattered radiation 1, 2
• Modern evidence indicates that abdominal shielding for chest X-rays provides no meaningful benefit and may require repeat imaging if positioning is compromised—lead shielding applied externally to the pelvis will not intercept scattered radiation from chest imaging, as fetal exposure comes from scattered radiation emanating from the directly exposed chest structures 1, 2
• Avoid direct radiation exposure to the abdomen and pelvis through proper positioning 1

Common Pitfalls to Avoid

• Do not allow unnecessary anxiety to lead to diagnostic delay—counsel the patient that chest X-ray radiation is equivalent to a few days of natural background exposure and that missing a serious maternal condition poses far greater risk 1, 2
• Do not rely on D-dimer to exclude pulmonary embolism in pregnancy, as it has inadequate sensitivity and specificity due to physiologically elevated levels throughout pregnancy 3, 1
• Pregnancy testing within 72 hours is only necessary for fluoroscopic interventional procedures that may deliver doses above 100 mGy, not for standard chest radiography 1
• Document the clinical indication clearly in the medical record, noting that risks and benefits were discussed with the patient 1, 2

Additional Considerations

• Chest radiography during first and second trimesters does not require pregnancy testing, as the fetal dose is negligible 1
• Diagnostic X-rays pose no risk to lactation, and breastfeeding does not need to be discontinued 1
• The most sensitive time period for central nervous system teratogenesis is between 10 and 17 weeks of gestation, but chest X-ray doses are so far below harmful thresholds that this timing consideration is clinically irrelevant 4
• Rare consequences of prenatal radiation exposure at diagnostic levels include only a very slight increase in childhood leukemia risk (estimated at one additional cancer death per 1,700 exposures at 10 mGy), which is orders of magnitude higher than chest X-ray exposure 5