Is it safe to have a chest x-ray at 27 weeks of pregnancy (obstetrics)?

Chest X-Ray at 27 Weeks Pregnancy is Safe

Yes, proceed with the chest x-ray without hesitation—the fetal radiation exposure is extraordinarily small (less than 0.01 mGy) and represents approximately 1/5,000,000th of the established safety threshold for fetal harm. 1

Radiation Dose Context

• The fetal dose from a standard chest x-ray is less than 0.01 mGy, which is negligible 2, 1
• The established danger threshold for fetal injury is 50-100 mSv (50,000-100,000 mGy)—all standard radiological tests fall well below this figure 2, 3
• At 27 weeks gestation, you are in the third trimester where organogenesis is complete, further reducing theoretical concerns 2

Clinical Decision Framework

The risk of missing a potentially serious maternal diagnosis (pneumonia, pulmonary embolism, cardiac disease) far outweighs the negligible radiation risk to the fetus. 2, 1

• Proceed with chest x-ray when clinically indicated for acute symptoms such as dyspnea, cough, suspected pneumonia, or pulmonary embolism evaluation 1
• Delaying or avoiding necessary imaging poses greater risk to both mother and fetus than the radiation exposure itself 1
• The radiation exposure from a chest x-ray is equivalent to just a few days of natural background radiation 1

Technical Considerations

• Use the ALARA principle ("as low as reasonably achievable") to minimize exposure, though the dose is already extremely low 2
• Abdominal shielding provides no meaningful benefit for chest x-rays, as fetal exposure comes from scattered radiation from chest structures, not direct beam exposure 1
• Collimate the field to the area of interest and avoid direct radiation to the abdomen through proper positioning 1

Common Pitfalls to Avoid

• Do not delay diagnostic imaging due to unnecessary anxiety—counsel the patient that the radiation dose is minuscule and that missing a serious maternal condition poses far greater risk 1
• Document the clinical indication clearly in the medical record and note that risks and benefits were discussed 1
• Avoid requiring repeat imaging due to improper positioning from unnecessary shielding attempts 1

Documentation

• Record the clinical indication for the examination 2
• Note that the patient was counseled about the negligible radiation risk 1
• Document that the benefit of diagnosis outweighs the minimal theoretical risk 2