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

Chest X-ray Safety During Pregnancy

A chest X-ray is safe during pregnancy as the fetal radiation exposure is extremely low (<0.01 mGy), far below the 50 mGy threshold where adverse fetal outcomes might be detected. 1, 2

Radiation Exposure from Chest X-ray

• Chest X-ray delivers minimal radiation to the fetus:
  • Fetal dose is <0.01 mGy 2, 3
  • This is approximately 5,000 times lower than the 50 mGy threshold for detectable adverse fetal outcomes 1
  • The distance between the chest and the uterus significantly reduces fetal exposure 1

Safety Measures to Minimize Exposure

When performing a chest X-ray during pregnancy:

1. Use proper abdominal shielding:

   • Lead apron (0.25-0.5 mm lead equivalent) should be used to shield the abdomen and pelvis 1
   • Ensure complete coverage of the abdomen

2. Optimize technique:

   • Strict collimation of the X-ray field to the chest area 1
   • Use lowest dose settings compatible with diagnostic image quality 1
   • Minimize exposure time and number of projections 1
   • Follow ALARA principle (As Low As Reasonably Achievable) 2

3. Documentation:

   • Record the radiation dose in the medical record, even though the fetus is not in the field of view 1

Clinical Context and Recommendations

• Chest X-ray should only be obtained if other methods fail to clarify the cause of respiratory symptoms 2
• No need to avoid or delay necessary chest X-rays during pregnancy, as the benefit of proper diagnosis typically outweighs the minimal risk 4, 5
• Non-urgent radiologic testing is best avoided between 10-17 weeks of gestation (most sensitive period for CNS development), though chest X-ray risk remains minimal even during this period 4

Alternative Imaging Considerations

• Ultrasound and MRI (without gadolinium) are preferred first-line options during pregnancy when applicable 1
• For respiratory or cardiac conditions requiring chest imaging, chest X-ray remains appropriate due to minimal fetal exposure 6

Patient Counseling

• Provide concrete information about radiation doses to alleviate anxiety 1
• Explain that the fetal dose from a chest X-ray is less than one day of natural background radiation 5
• Emphasize that this level of exposure has not been associated with increased risk of congenital malformations, growth restriction, or pregnancy loss 5, 3
• The theoretical increased risk of childhood cancer is extremely small (estimated at one additional cancer death per 1700 exposures at 10 mGy - chest X-ray exposure is 1000 times lower) 5

The evidence clearly demonstrates that chest X-ray during pregnancy, when clinically indicated, poses minimal risk to the developing fetus and should not be avoided when medically necessary.