In 2011, as the tsunami-damaged reactors at Japan’s Fukushima Daiichi nuclear power plant began leaking radioactive particles, that nation’s pregnant women ran for the hills—or at least for faraway cities like Osaka. Moms-to-be in the U.S. may be more worried about X-rays and their high-energy ionizing radiation that could damage DNA or the low-energy microwave radiation from cellphones and Wi-Fi.
Here are some guidelines for a safer pregnancy:
Medical X-rays are the most common source of man-made radiation exposure, and obstetric experts suggest avoiding them when possible. There’s generally a low increase in risk of birth defects when a mom-to-be has X-rays, though it depends on timing (earlier is riskier) and amount of exposure.
In utero exposure can increase the offspring’s cancer risk later in life, and while the risk from a single X-ray is tiny, you’ll want to err on the side of caution.
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“X-rays save lives when used appropriately,” says epidemiologist and toxicologist Devra Davis, Ph.D., M.P.H., who wrote about radiation in The Secret History of the War on Cancer and Disconnect. “Used inappropriately, they result in avoidable cancers.”
Davis advises asking for diagnostic alternatives, such as MRI or ultrasound; postponing routine mammograms and dental X-rays; and avoiding a CAT scan—the equivalent of hundreds of chest X-rays—unless medically necessary.
If you had an X-ray before learning you were expecting, don’t panic: If the embryo were damaged, you likely would have miscarried, perhaps before you even knew you were pregnant.
Some women worry about those full-body scanners at the airport, but the ionizing radiation exposure they pose is “truly trivial,” Davis says. It would take about 50 trips through an airport backscatter X-ray to receive the amount you’d get from a single dental X-ray, though you might want to opt for the pat-down because scanners are not always perfectly calibrated or operated.
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One source of radiation is almost always with you: your cellphone. While a phone’s radiation is the microwave rather than ionizing type, emissions may still damage DNA over the long term. Turkish researchers who studied lab animals found that prenatal exposure affected the offspring’s eyes, brain, liver and skin.
Davis recommends that pregnant women keep cellphones well away from their abdomens and that moms not let babies play with the phones.
“You don’t wait for a car crash before putting your baby in car seat,” she says. “You need to take similar precautions with cellphones. Distance is your friend.” The same may be true of iPads, which are designed and tested for use eight inches from the adult body.
Davis also suggests turning off your phone and Wi-Fi router at night to minimize exposure, especially during sleep, since that’s when the body does a lot of its DNA repair. Eating green, leafy vegetables, like broccoli, and sleeping in the dark so the body can produce more melatonin can help undo DNA damage.
“You’re not doomed, no matter how much you’ve been using that phone,” Davis explains. “Nature has endowed us with DNA repair.”