Does an X-ray (X-radiation) affect pregnancy?

X-ray Effects on Pregnancy

X-rays pose minimal risk to pregnancy when fetal exposure is below 50 mGy, which is the case for most diagnostic imaging procedures, especially those not directly targeting the abdomen or pelvis. 1 Proper safety measures and appropriate shielding can further reduce any potential risks.

Radiation Exposure Risks During Pregnancy

Fetal Dose Thresholds

• Fetal radiation exposure below 50 mGy is not associated with detectable increases in adverse fetal outcomes 1
• Adverse effects occur at much higher doses:
  • Embryonic death: 100-500 mGy 2
  • Mental retardation risk: Significant at doses above 100 mGy, particularly between weeks 8-15 of gestation 2
  • Malformations: Risk increases at doses above 150 mGy 1
  • Potential pregnancy termination consideration: Doses above 200 mGy 1

Typical Fetal Doses from Common X-ray Procedures

Procedure	Typical Fetal Dose
Chest X-ray	<0.01 mGy [1]
Extremity or head/neck X-rays	Negligible [1]
Dental X-rays	0.009-6.9 μGy (extremely low) [3]
CT chest	0.3 mGy [1]
CT abdomen/pelvis	13-25 mGy [1]

Safety Measures and Recommendations

Screening and Assessment

• All women of menstrual age (typically 12-50 years) should be questioned about pregnancy status before X-ray procedures 2
• Pregnancy tests are recommended within 72 hours of high-dose procedures (e.g., fluoroscopic interventions) that may deliver >100 mGy 2
• Chest radiography during first and second trimesters and extremity or head/neck radiography may not need to be altered by pregnancy status 2

Protective Measures

• Use lead apron (0.25-0.5 mm lead equivalent) to shield the abdomen and pelvis 1
• Strictly collimate the X-ray field to the area of interest 1
• Follow the ALARA principle (As Low As Reasonably Achievable) 2
• Use the lowest dose settings compatible with diagnostic image quality 1

Alternative Imaging Modalities

• Ultrasound and MRI (without gadolinium) are preferred first-line options during pregnancy 1
• For gynecologic or obstetric conditions, transvaginal/transabdominal ultrasound is recommended as first-line 1

Special Considerations

Breastfeeding

• Diagnostic X-rays pose no risk to lactation 2
• Breastfeeding after iodinated contrast is considered safe (less than 0.01% of CT contrast present in breast milk) 1
• Lactating women do not need to discontinue breastfeeding after receiving intravascular iodinated contrast 2

Nuclear Imaging Concerns

• Radioactive iodine readily crosses the placenta and can injure the fetal thyroid gland 2
• Technetium-99m has a shorter half-life and causes less fetal exposure 2
• For nuclear cardiology perfusion imaging, Rb82 PET would cause the least fetal exposure 2

Patient Communication

• Provide concrete information about radiation doses and risks to alleviate anxiety 1
• Explain that with proper shielding and when the X-ray is not directed at the abdomen/pelvis, fetal exposure is negligible 1
• Document radiation dose in the medical record, even when the fetus is not in the field of view 1

Common Pitfalls to Avoid

1. Unnecessary avoidance of clinically indicated imaging: Pregnancy is never a reason to avoid or postpone a clinically justified radiographic examination 3

2. Failure to shield: Always use appropriate lead shielding for the abdomen and pelvis when performing X-rays on pregnant patients 1

3. Overestimation of risk: Most diagnostic X-rays deliver doses far below thresholds for deterministic effects 4

4. Inadequate documentation: Always record radiation exposure in the medical record 1

5. Overlooking alternative imaging options: Consider non-ionizing alternatives like ultrasound or MRI when appropriate 1