Are full-body scanners at airports safe for pregnant women?

These scanners work in two ways. One type uses nonionizing electromagnetic radiation (millimeter waves), a form of energy similar to that used in radar im­ages and radio signals. This type of radia­tion, which has been used for a century, has no known health effects. The other type of scanner uses "back scatter" ionizing radiation, which exposes an individual to a very weak X-ray signal. The radiation emitted from the scanner is weak enough that the X-ray doesn't penetrate the body. With either type of machine, there's no evidence of risk to the developing fe­tus. The risk to the mother, even with re­peated exposures, would be immeasur­ably small.