Can a pregnant patient at 36 weeks gestation request a chest x-ray with an abdominal shield?

Chest X-Ray in Pregnancy at 36 Weeks: Safety and Shielding

Yes, a pregnant patient at 36 weeks can safely request and receive a chest x-ray, but abdominal shielding provides no meaningful benefit and may actually be counterproductive. 1

Radiation Exposure Reality

The fetal radiation exposure from a standard chest x-ray is extraordinarily small and poses negligible risk:

• A chest x-ray delivers less than 0.01 mGy to the fetus, which represents approximately 1/5,000,000th of the established safety threshold 1
• The safety threshold for fetal harm is 50-100 mGy (50,000-100,000 mGy), meaning a chest x-ray delivers far less than 0.02% of the dose that could cause concern 1, 2
• Chest radiography during any trimester may be performed safely with minimal fetal risk 2

The Abdominal Shield Misconception

Abdominal shielding for chest x-rays is not recommended and may be harmful:

• Lead shielding applied externally to the pelvis and abdomen will not intercept scattered radiation from chest imaging, as fetal exposure comes from scattered radiation emanating from the directly exposed chest structures 3
• Modern evidence indicates abdominal shielding provides no meaningful benefit and may require repeat imaging if positioning is compromised 1
• Shielding can paradoxically increase both maternal and fetal radiation dose by interfering with automatic exposure control systems, as demonstrated in phantom studies showing a 47% increase in effective dose and increased fetal absorbed dose (0.10 vs. 0.12 mGy) with shielding 4

Clinical Decision Framework

Proceed with chest x-ray without hesitation when clinically indicated:

• The risk of missing a potentially serious maternal diagnosis far outweighs the negligible radiation risk 1
• Delaying or avoiding necessary imaging poses greater risk to both mother and fetus than the radiation exposure itself 1
• At 36 weeks gestation, the patient is well past the most sensitive period for central nervous system teratogenesis (10-17 weeks), further reducing any theoretical concerns 5

Proper Technique

Focus on optimal imaging technique rather than shielding:

• Collimate the field to the area of interest to ensure fetal exposure is minimized 3
• Avoid direct radiation exposure to the abdomen and pelvis through proper positioning 3
• Document the clinical indication clearly in the medical record, noting that risks and benefits were discussed with the patient 1

Patient Counseling

Counsel the patient that:

• Chest x-ray radiation is equivalent to a few days of natural background exposure 1
• Missing a serious maternal condition poses far greater risk than the negligible radiation from chest imaging 1
• The cumulative dose from a chest x-ray (0.00007 rad) is far below the accepted cumulative dose during pregnancy (5 rad) 5