In Japan, Pregnant Women at Increased Risk for Radiation Exposure, Experts Warn
Pregnant women are at a greater risk because unborn babies' cells multiply more rapidly than adults, making them more vulnerable to birth defects, cognitive problems and cancer, according to the Journal's health blog.
Exacerbating the risk is the fact that radiation can affect the fetus in a number of different ways, according to the Journal.
Chandon Guha, vice chairman of the radiation oncology department at Montefiore Medical Center and Albert Einstein College of Medicine, tells the Journal radiation can pass directly to the fetus through the woman's body, similar to a diagnostic X-ray, though the woman's abdomen does shield the fetus from exposure.
But of equal concern are "damaging particles that are released from nuclear accidents and (can) be carried by the wind. If those are inhaled, ingested or absorbed into the skin, they can reach the fetus through the circulatory system of the mother and cause damage," the Journal writes.
The risk of adverse effects on an unborn baby varies at different stages in the pregnancy, with the first 10 to 14 days posing damage that can be fatal, according to the Journal. That's magnified by the fact that the woman might not even know she is pregnant.
For harm to happen, though, a woman would likely require a dose of radiation many times higher than is given in most diagnostic tests, such as a pelvic CT. And fetuses that are exposed to radiation during this period and survive aren't likely to develop related birth defects, brain damage or stunted growth, according to the Centers for Disease Control.
After the 16th week of pregnancy, radiation exposure is unlikely to produce the same kind of problems, unless the dose is equivalent to about 5,000 chest X-rays, the CDC tells the Journal. And, after 26 weeks, the fetus "is no more sensitive to the effects of radiation than are newborns," with birth defects unlikely and "only a slight increase in the risk of having cancer later in life expected," the CDC says.
But very high doses of radiation would have the same ill effects as they would on a baby.
Experts, however, warn that the news coming out of Japan changes frequently, making it difficult to pinpoint the exact levels of radiation.
"For convenience, we assume any radiation dose gives us an increased risk of cancer," Kathryn Higley, head of the department of nuclear engineering and radiation health physics at Oregon State University, tells Time.
In areas experiencing high concentrations of radiation, she adds, "there is no question that really elevated levels do affect the embryo and fetus."
Higley and other experts tell Time pregnant women and parents of little kids would be wise to heed advisories regarding evacuation zones.
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