Dose-response relationship between body temperature and birth defects in radiofrequency-irradiated rats.
Lary-JM; Conover-DL; Johnson-PH; Hornung-RW
Bioelectromagnetics 1986 Feb; 7(2):141-149
The dose/response relationship between maternal body temperature induced by radiofrequency irradiation and birth defects was studied in rats. Pregnant Sprague-Dawley-rats were irradiated for 10 to 40 minutes on day 9 of gestation in a 27.12 megaHertz field at a magnetic field strength of 55 angstroms a minute and an electric field strength of 300 Volts per minute. Animals were irradiated until colonic temperatures reached target temperatures of 41.0, 41.5, 42.0, 42.5, or 43.0 degrees-C. Control animals were sham irradiated or were untreated. All rats were killed on gestation day 20 and the number of implantations, live fetuses, and dead or resorbed conceptuses were determined. Dose/response curves based on maternal colonic temperature were obtained for external and major malformations per litter and prenatal mortality. At colonic temperatures above 41.5 degrees the incidence of dead or malformed fetuses increased directly with the temperature. The threshold temperature for prenatal mortality was determined by probit analysis at 41.7 degrees. The threshold for external malformations was 41.4 degrees. For visceral malformations the threshold was estimated at around 41.5 degrees. A few of the pregnant rats died after exposure to 43.0 degrees. Malformations observed in the experimental groups were usually of the head. The authors conclude that the incidence of birth defects and prenatal mortality following hyperthermia induced by radiofrequency irradiation is directly related to maternal body temperature once a temperature threshold around 41.5 degrees is exceeded.
NIOSH-Author; Laboratory-animals; Biological-monitoring; Radiation-exposure; Temperature-effects; Dose-response; Monitoring-systems; Mortality-rates; Thermal-effects; Physiological-response; Rodents