Answer to Question #11887 Submitted to "Ask the Experts"
Category: Pregnancy and Radiation — Flying
The following question was answered by an expert in the appropriate field:
Could the cosmic ray exposure detailed below have had any effect on the brain of my unborn child?
Home country: United States
Exposure: Cosmic rays while flying one-way, trans-Pacific, from Dallas to New Zealand. Three flight segments on the trip: 3 hours + 13 hours + 1 hour. The online calculator I used gave a total value of 57.6 microsieverts (µSv).
History: Two children, all normal.
Pregnancy stage: Second trimester.
Could this trip in any way have affected the fetus's IQ or rate of brain development? I read that during certain weeks, the fetus's brain is especially sensitive to radiation. What if the trip was during those weeks? Note that this trip happened a long time ago, and I don't remember which week of my pregnancy it was.
A radiation dose of 57.6 µSv is well below the radiation dose level known to cause brain development effects. In fact for comparison, during the nine months of gestation, the baby receives about 2,300 µSv of radiation dose from natural background radiation sources alone. The radiation dose limit in the United States for a person who is exposed occupationally to radiation is 5,000 µSv (in addition to natural background radiation dose).
As reported in scientific literature, the radiation exposure that could cause possible developmental effects on the brain would occur from 8 to 15 weeks of embryonic age at radiation doses above 200,000 µSv. This is orders of magnitude above the dose your baby received from the flight.
In summary, radiation doses received while flying are well below the radiation doses reported in literature that would cause a deleterious effect.
Certified Medical Health Physicist
Hall EJ, Giaccia AJ. Radiobiology for the radiologist. 6th ed. New York: Lippincott, Williams & Wilkins; 2006.