Two strains of mice were exposed to magnetic fields (50 Hz or 20 kHz) according to different time schedules. Experiment 1: From the first day of conception until 280 days of age 50 Hz); experiment 2: 140 days, starting at an age of 84 days (50 Hz); experiment 3: for 20, 30, 40, and 60 days, respectively, starting at an age of 29 days (50 Hz or 20 kHz); experiment 4: for 1, 2, or 4 days, respectively,starting at an age of 21 day (50 Hz); experiment 5: for 90 days, starting at an age of 30 day (50 Hz).
Experiment 1*: throughout pregnancy + 280 days of age, experiment 2: 140 days, experiment 3: 20 days, 30 days, 40 days and 60 days, experiment 4: 1 day, 2 days and 4 days, experiment 5: 90 days
*In experiment 1, mice mated while being exposed to magnetic field. The exposure was continued with the pregnant mice until day 20 after birth and was carried on with the off spring till 280 days of age. In experiment 2: adult mice were exposed. In experiment 3, 4 and 5, young mice were exposed.
A significantly lower body weight as well as liver and kidney weights were found in male mice exposed during fetal stages up to 280 days These results were not seen in female mice (exp. 1). A lower growth was found in mice exposed for 140 days (exp. 2). Kidney and liver weights were significantly reduced in mice exposed for 90 days (exp. 5). The authors conclude that the observed effects depend on exposure time. In addition, young mice and male mice were found to be more senistive. The effects of 50 Hzexposure where larger than at 20 kHz.