Effects of prenatal exposure to 50 Hz magnetic fields on development in mice: I. Implantation rate and fetal development

The effect of an extremely low frequency (ELF) magnetic field on the fertility of adult male and female Swiss mice was investigated. Adult male and female mice were exposed to a 50 Hz sinusoidal magnetic field at approximately 25 microT (rms) for 90 days before they were mated with unexposed counterparts. There were no exposure related effects on the fertility of male or female mice. The number of implantation sites, viable fetuses, and the total number of resorptions were not significantly affected in females impregnated by males exposed to the 50 Hz magnetic field as compared with the control group. The number of implantation sites, viable fetuses and the total number of resorptions in exposed females were also not statistically different from the control group. There were no significant effects on the weights of the testes, seminal vesicles, preputial gland or body weights of males exposed to 50 Hz magnetic field. Furthermore, body and uterine weights were not affected in females exposed to 50 Hz field; however, ovarian weight was significantly increased in females exposed to the same field. These results suggest that exposure of male and female mice to low frequency magnetic field had no adverse effects on fertility and reproduction in mice.

Section: Discussionsupporting

confidence: 91%

“…At the same time, other studies have reported no harmful reproductive effects [Wiley et al, 1992;Kowalczuk et al, 1994;Ryan et al, 1999].…”

Section: Introductionmentioning

confidence: 92%

Long‐term exposure of male and female mice to 50 Hz magnetic field: Effects on fertility

Elbetieha

Al-Akhras

Darmani

2002

“…This set of studies does not provide data supportive of the hypothesis that MF exposure, under the conditions tested here, affects rat dams or fetuses. It also does not support the hypothesis that circularly polarized MF have more adverse effects on Kowalczuk et al [1994] reported a significant increase in the body weights of CD-1 mice fetuses exposed to 50 Hz, 20 mT MF. In contrast, Ryan et al [1996] found a small but statistically significant reduction in the body weights of male and female SD rat fetuses in the 60 Hz, 200 mT exposure group, but not in the 2 mT and 1 mT exposure groups.…”

Section: Discussioncontrasting

confidence: 62%

“…Rommereim et al [1996] exposed pregnant rats to 60 Hz, 1 mT sinusoidal horizontal MF and found a significantly decreased number of fetuses per litter in one replicate, but not in the other. Kowalczuk et al [1994] exposed pregnant CD-1 mice to 50 Hz, 20 mT sinusoidal vertical MF, and found no effects on the number of fetuses, fetal mortality and sex ratio, but the body weight of live fetuses was significantly higher and the incidence of external abnormalities was significantly lower in the exposed group. In contrast, Ryan et al [1996] found a small but statistically significant reduction in the body weights of male and female fetuses in the 60 Hz, 200 mT exposure group, but not in the 2 mT and 1 mT exposure groups in rats.…”

Section: Introductionmentioning

confidence: 93%

Studies of 50 Hz circularly polarized magnetic fields of up to 350 μT on reproduction and embryo‐fetal development in rats: Exposure during organogenesis or during preimplantation

Negishi

Imai

Itabashi

et al. 2002

Groups of mated female Sprague-Dawley rats were simultaneously exposed to 0 (sham exposed), 7, 70, or 350 microT (rms) circularly polarized 50 Hz magnetic fields (MF) for 22 h/day on gestational day 8-15, the period of rat fetal organogenesis (organogenesis study) or from day 0 to day 7 of gestation, the rat preimplantation period (preimplantation study). Developmental toxicity was assessed on gestational day 20. Identical experiments were repeated to confirm reproducibility of both studies. In both studies, statistically significant differences between exposed and sham exposed animals were observed in several measured parameters; however, these differences only appeared in one, but not both replicate experiments and generally at only an isolated exposure level. Because these differences were not reproducible and did not show a dose response relationship, they were not considered related to MF exposure. In the organogenesis study, lower kidney weights of dams were seen at 70 and 350 microT in Experiment 1. Lower dam liver weights and lower mean body weights of viable female and male fetuses were seen at 70 microT in Experiment 2. Otherwise, there were no differences in these parameters or in group means for fetal loss after implantation, number of viable fetuses, fetal body weight and sex ratio, incidences of external, visceral, and skeletal abnormalities or variations, or tissue abnormalities after histopathological examination. In the preimplantation study, dam health and indices for reproduction and embryo-fetal development, including pre or postimplantation loss, number and body weight of live fetuses, and sex ratio, external, skeletal abnormalities and variations, and skeletal ossification did not differ. Dam inorganic phosphorous concentration at 350 microT was elevated in one experiment and depressed in another. In one experiment, visceral abnormalities, primarily thymic remnant in neck and accessory liver lobe, were increased in the 7 microT group. Based on these results from two studies, we conclude that circularly polarized 50 Hz MF exposure of up to 350 microT during the fetal organogenesis or during the preimplantation period does not affect reproduction and embryo-fetal development in Sprague-Dawley rats.

“…Kowalczuk et al [1994] reported a significant increase in the body weight of CD-1 mice fetuses exposed to 50 Hz, 20 mT magnetic field. Contrary to the above, Kato et al [1998] found a small but statistically significant reduction in the body weights of male and female SD rat fetuses among the 60 Hz, 200 mTexposure group, but not in the 2 mT and 1 mT exposure groups.…”

Section: Discussionmentioning

confidence: 96%

Teratological studies of prenatal exposure of mice to a 20 kHz sawtooth magnetic field

Kim

Song

Kim

et al. 2004

In order to evaluate the importance of gestational age in possible effects due to exposure to a 20 kHz sawtooth magnetic field, pregnant ICR mice at gestational 2.5-15.5 days post-coitus, which is the most sensitive stage for the induction of major congenital malformations, were exposed in a carrousel irradiator. The mice were exposed to a 20 kHz intermediate frequency (IF) sawtooth magnetic field had a 6.5 microT peak intensity for 8 h/day. The animals were sacrificed on the 18th day of gestation; and the fetuses were examined for mortality, growth retardation, changes in head size, and other morphological abnormalities. From the above conditions, it is concluded that the exposure to a 20 kHz sawtooth magnetic field with 6.5 microT peak intensity does not inflict any adverse effect on fetuses of pregnant mice.