Rats: A total of 120 rats were randomly divided into four groups (n=30 per group; 15 females and 15 males, respectively): 1) sham exposure, 2) 30 µT magnetic field, 3) 100 µT magnetic field and 4) 500 µT magnetic field. Blood was taken before, after 12 and after 24 weeks of exposure to determine hormone concentrations (7 females and 7 males per group, respectively). Afterwards, rats were killed and reproductive organs were taken for further analyses (10 females and 10 males, respectively). Sperm count was performed in 5 males per group.
Several experiments were performed with mice:
Mice (hormones): 64 mice were randomly divided into the same four exposure groups as rats (n=16 per group; 8 females and 8 males, respectively). Blood was taken before and after exposure.
Mice (pregnancy rate): 315 mice were mated in different combinations (10 females and 5 males, respectively; experiments were independently repeated for three times): a) females group 1 x males group 1, b/c/d) females group 1 x males group 2/3/4, and e/f/g) females group 2/3/4 x males group 1 (same exposure groups as rats). Mice were mated after exposure. After 8 days of pregnancy, dams were killed and implanted embryos counted.
Mice (foetal development): 120 female and 60 male mice were mated and female mice were exposed to the above mentioned exposure groups afterwards (n=30 per group). On pregnancy day 18, dams were killed and fetuses examined.
Mice (development of pups): 60 female mice and 30 male mice were mated. The newborn pubs were randomly divided into the same four exposure groups as above (n=30 per group) and exposed for three weeks with their mothers.
Exposure duration: 20 hours/day for 24 weeks
Exposure duration: 20 hours/day for 12 weeks
Exposure duration: 20 hours/day for 8 weeks
Mice (pregnancy rate)
Exposure duration: 20 hours/day for 18 days
Mice (foetal development)
Exposure duration: 20 hours/day for 3 weeks
Mice (development of pups)
|Chamber||cages were made of plastic (length 45 cm x width 35 cm x height 20 cm); four rats per cage|
|Setup||Four exposure devices (0, 30, 100, 500 µT) were run simultaneously but in different rooms; an exposure device consisted of five layers made with two beams of copper wires (length 200 cm x width 100 cm x height 200 cm); wires were fixed tightly to the framework to reduce vibration and noise; a plastic rack (140 cm x 70 cm x 200 cm) with 4 floors (each floor was 35 cm high) was set inside the exposure device; uniform area for magnetic flux density (± 3%) for each floor was 150 cm x 50 cm (length x width)|
|Sham exposure||A sham exposure was conducted.|
|Additional info||For sham exposure, animals were put in an exposure device without current|
|Exposure duration||20 hours/day for 3 weeks|
|Additional info||Mice (development of pups)|
No significant differences were found between exposed rats and mice and sham exposed ones.
The authors conclude that power frequency magnetic fields did not have any influence on fertility and developmental parameters in mice.