Radiation and the Human Fetus

Due to the rapid growth of a fetus, it is more sensitive to radiation than an adult. In humans, the major effects on the fetus, from exposure to radiation is miscarriage, birth defects, mental retardation, poor growth and weight of the fetus, and the possibility of cancers such as leukemia in childhood. Of course, not all exposures to radiation result in these problems.

Risk Related to the Gestational Age:

Early Gestation / First Trimester -- At this point, the rate of fetal growth is very rapid and the fetus, as an organism, is at its most radiation-sensitive stage if fetal demise is taken as an end-point. The incidence of fetal wastage consequential to radiation exposure at this stage of gestation is not known, since (a) many women were never aware they were pregnant at the time of the exposure or miscarriage, and (b) the "background" rate of miscarriage is believed to be high (25 - 50 percent of conceptions). It is believed that radiation injury during early gestation is an "all-or-nothing" effect.

Second Trimester -- During this period, the overall growth rate of the fetus has slowed. However, the major organ systems are beginning to differentiate. From a standpoint of future development, the fetus is in its most sensitive stage. The incidence of gross congenital malformations and mental retardation are dose-related and appear to have thresholds; i.e. doses below which the incidence above "background" is not elevated.

Third Trimester -- Irradiation during this period may deplete cell populations at very high doses (over 50 rem), but will not result in gross organ malformations.[1]  Obviously, the amount of the ionizing radiation is also a factor, the higher the dose, the higher the risk of problems. It is only common sense to avoid radiation when
possible. With the hundreds of backscatter x-ray machines and the full body scanners being installed in airports around the world, why subject your body to damaging radiation? We offer products to protect the most sensitive tissues from energies used by security, dental and medical imaging equipment.

[1] http://www.safety.duke.edu/radsafety/fdose/fdrisk.asp

For more information:
http://www.jlab.org/div_dept/train/rad_guide/effects.html

Breck@RockyflatsGear.com
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