Neural and behavioral teratological evaluation of rats exposed to ultra-wideband electromagnetic fields

Several investigators have reported teratologic effects of electromagnetic field exposure. The majority of these studies have been performed at levels of exposure that could produce substantial heating of the animals. New and unique sources of ultra-wideband (UWB) electromagnetic fields are currentl y being developed and tested that are capable of generating nonthermalizing , high-peak-power, microwave (MW) pulses with nanosecond (ns) pulse widths, picosecond tps) rise times, and an UWB of frequencies. Our study was perfo rmed to determine if teratological changes occur in rat pups as a result of (i) daily UWB exposures during gestation days 3-18, or (ii) as a result of both prenatal and postnatal (10 days) exposures. Dams were exposed either to (i) UWB irradiation from a Kentech system that emitted a 55 kV/m-peak E field, 300 ps rise time, and a 1.8 ns pulse width, average whole-body speci fic absorption rate 45 mW/kg; (ii) sham irradiation; or (iii) a positive co ntrol, lead (Pb) acetate solution (2000 mu g/ml) continuously available in the drinking water. Offspring were examined for ontogeny (litter size, sex- ratios, weights, coat appearance, tooth-eruption, eye-opening, air-righting , and ultrasonic stress vocalizations). Male pups were tested on various pe rformance measures (locomotor, water-maze learning, and fertilization capab ilities). The pups postnatally exposed were examined for hippocampal morpho logy and operant behavior. Behavioral, functional, and morphological effect s of UWB exposure were unremarkable with these exceptions: (i) The UWB-expo sed pups emitted significantly more stress vocalizations than the sham-expo sed pups; (ii) the medial-to-lateral length of the hippocampus was signific antly longer in the UWB-exposed pups than in the sham-exposed animals; (iii ) male offspring exposed in utero to UWB mated significantly less frequentl y than sham-exposed males, but when they did mate there was no difference i n fertilization and offspring numbers from the sham group. There does not a ppear to be a unifying physiological or behavioral relationship among the s ignificant differences observed, and our findings could be due to the expec ted spurious results derived when a large number of statistical comparisons are made. Significant effects found between our positive-controls and othe r groups on numerous measures indicates that the techniques used were sensi tive enough to detect teratological effects. Published 2000 Wiley-Liss, Inc .