Independent of the general problem of security theater, are you actually concerned about electromagnetic-based scanning on pregnant women? All the ionizing radiation-based scanners were (somewhat ironically) moved to prisons about two years ago: http://www.pbs.org/newshour/rundown/banned-airport-full-body... Unless you're concerned about wi-fi and cellular signals affecting pregnancy, you probably don't need to stay up worrying about millimeter-wave scanners.