Teratogenic effects of 27.12 MHz radiofrequency radiation in rats.

High-intensity 27.12 MHz radiofrequency (RF) radiation was determined to be teratogenic in rats during most of the gestation period. Eight groups of pregnant rats were exposed to a magnetic field strength of 55 amps/meter and an electric field strength of 300 volts/meter on gestation days 1, 3, 5, 7, 9, 11, 13, or 15. Exposures ceased once the dam's colonic temperature reached 43.0 degrees C (about 20-40 minutes' duration). Eight matching control groups were sham-irradiated for 30 minutes at 0 amps/meter and 0 volts/meter. An additional group of pregnant rats received no treatment. With one exception, no significant differences occurred between sham-irradiated and untreated control groups. RF exposure, however, caused a significant incidence of fetal malformations throughout the postimplantation period (days 7 through 15). It also caused a low but significant incidence of preimplantation malformations. Fetal weight and crown-rump length were reduced in all postimplantation exposure groups but were not affected by preimplantation exposure. The incidence of dead or resorbed fetuses was significantly increased in rats irradiated on days 7 or 9. The effects observed appeared to be caused by RF-induced hyperthermia in the treated dams. Since a number of industrial, scientific, and medical devices operating at or near 27.12 MHz can cause hyperthermia in humans, women of childbearing age should avoid exposure to RF-radiation levels that exceed current US occupational standards.