Is radiation allowed during pregnancy?

Radiation Use During Pregnancy: Guidelines and Safety Considerations

Radiation therapy should generally be postponed until after delivery unless there is an urgent clinical need, and even then should only be considered when the treatment site is located sufficiently far from the uterus with adequate shielding. 1

Radiation Risks to the Fetus

Radiation exposure during pregnancy poses several potential risks to the developing fetus:

• Fetal malformations and mental retardation: Risk increases significantly at doses >100-200 mGy 1
• Intrauterine growth restriction: Can occur at higher radiation doses 1
• Childhood cancer: Even lower doses may increase risk of childhood malignancies 1
• Fetal death: Possible at very high doses 1

The severity of these risks depends on three critical factors:

• Fetal dose received
• Gestational age at exposure
• Radiation field extension 1

Safety Thresholds and Timing Considerations

Dose Thresholds

• <50 mGy: Generally considered safe with no evidence of increased risk for congenital malformations, intellectual disability, growth restriction, or pregnancy loss 1
• 50-100 mGy: Risk is less clear, caution advised 1
• >100-200 mGy: Significantly increased risk of fetal malformations and mental retardation 1

Gestational Age Considerations

• First 14 days after fertilization: Intact survival without abnormality or death are most likely outcomes even with exposure >50 mGy 1
• After first 14 days: Exposure >50 mGy may increase risk of congenital malformations, growth restriction, and intellectual disability 1
• Weeks 8-15 of gestation: Period of highest vulnerability for mental retardation 1

Recommendations for Different Clinical Scenarios

For Diagnostic Procedures

• Echocardiography is preferred as it doesn't involve radiation exposure 1
• If radiation-based diagnostic procedures are medically necessary, they should not be withheld as most properly performed diagnostic procedures present minimal risk 2
• When possible, delay procedures until after completion of major organogenesis (>12 weeks) 1

For Therapeutic Radiation (Cancer Treatment)

• Primary recommendation: Postpone radiation therapy until after delivery 1
• Consider radiation therapy during pregnancy only if:
  1. There is an urgent clinical need 1
  2. The tumor is located sufficiently far from the uterus 1
  3. Adequate shielding can be implemented 1
• Supradiaphragmatic radiotherapy: May be safer later in pregnancy 3
• Pelvic radiotherapy: Not appropriate during pregnancy 3

For Medical Personnel During Pregnancy

• Pregnant healthcare workers can safely continue working with radiation provided proper protection measures are followed 1
• Exposure limits for pregnant workers:
  • Maximum 0.5 rem (5 mSv) over entire pregnancy 1
  • Maximum 0.05 rem (0.5 mSv) in any single month 1
• Consider reducing exposure during weeks 8-15 of gestation 1

Protective Measures

For Patients

• Use proper shielding techniques
• Limit radiation exposure to absolute minimum necessary
• Consider alternative non-radiation diagnostic methods when possible

For Healthcare Workers

• Use appropriate lead aprons (consider maternity aprons) 1
• Maintain proper distance from radiation sources 1
• Wear two monitoring badges: one at neck outside lead apron and one at waist under lead apron 1
• Monitor exposure on a case-by-case basis using pocket ionization chambers 1

Common Pitfalls to Avoid

1. Unnecessary termination of pregnancy: Fetal doses below 100 mGy should not be considered a reason for terminating pregnancy 2
2. Withholding necessary diagnostic procedures: The risk to the mother of not performing a medically indicated procedure often exceeds the risk to the fetus 2
3. Inadequate shielding: Proper shielding techniques are essential to minimize fetal exposure
4. Failure to consult radiation safety experts: Advanced consultation between radiation oncologist, medical oncologist, obstetrician, and medical physicist is strongly recommended 1

In conclusion, while radiation exposure during pregnancy carries risks, with proper precautions and adherence to safety guidelines, necessary procedures can be performed with minimal risk to the fetus. The decision to use radiation during pregnancy should be made after careful consideration of the risk-benefit ratio, with priority given to maternal health while taking all possible measures to protect the developing fetus.