How does radiation exposure affect unborn babies?

What would cause a baby to be exposed to radiation?

Today, the most common source of prenatal radiation exposure is medical exams, such as a computerized axial tomography (CT or CAT) scan of the abdomen or pelvis, lower back X-rays, or standard pelvic X-rays. It can also come from the backscatter X-ray at the airport. Less common causes of radiation exposure could include nuclear power plant accidents, detonation of an atomic bomb or nuclear weapons testing.

Unborn babies are more susceptible to the health effects of radiation, especially in the very early weeks immediately following conception, since they are comprised of fewer cells, which are dividing rapidly, and therefore more likely to be disrupted by the effects of radiation. In turn, their development can be greatly impacted. This means that between the second and 18th week of pregnancy, mothers should be particularly cautious about radiation exposure [source: Centers for Disease Control and Prevention]. Since an unborn baby is still developing, radiation levels that may have no impact on the mother can harm them.

The most common effects of in utero radiation exposure are impaired growth, physical deformities like smaller head size, irregular brain performance, or cancers that may develop later in the baby's life [source: Classic]. Of the cancers associated with radiation exposure, leukemia and cancers of the thyroid, lung and breast are the most common [source: WebMD]. However, the womb sometimes serves as a safe house of sorts for the baby. It can shield the baby from the total amount of radiation the mother is being exposed to, limiting the harm caused.

If you're pregnant and are at all concerned about the possibility of being exposed to radiation, consult your doctor immediately. According to the Health Physics Society, common types and levels of radiation exposure include:

  • Natural background radiation for the average American each year = 3 millisievert (mSv)
  • Natural background radiation from living at high-altitudes, such as Denver: 6 mSv/year
  • CT of abdomen or pelvis= 7 to 14 mSv
  • Mammogram = 1 to 2 mSv
  • X-ray of lower back = 0.8 mSv
  • X-ray of chest = .1 to .6 mSv
  • One backscatter X-ray screening for security at an airport= 0.0038 mSv

The risks of radiation exposure can vary based on the gestational stage. Keep reading to learn more.