EFFECTS OF LOW-FREQUENCY MAGNETIC-FIELDS ON FETAL DEVELOPMENT IN CBA CA/

Effects of alternating magnetic fields (MFs) on the embryonic and feta l development in CBA/Ca mice were studied. Mated females were exposed continuously to a sinusoidal 50 Hz (13 mu T or 0.13 mT root mean squar e) or a sawtooth 20 kHz (15 mu T peak-to-peak) MF from day 0 to day 18 of pregnancy for 24 h/day until necropsied on day 18. Control animals were kept under the same conditions without the MF. MFs did not cause maternal toxicity. No adverse effects were seen in maternal hematolog y and the frequency of micronuclei in maternal bone marrow erythrocyte s did not change. The MFs did not increase the number of resorptions o r fetuses with major or minor malformations in any exposure group. The mean number of implantations and living fetuses per litter were simil ar in all groups. The corrected weight gain (weight gain without uteri ne content) of dams, pregnancy rates, incidences of resorptions and la te fetal deaths, and fetal body weights were similar in all groups. Th ere was, however, a statistically significant increase in the incidenc e of fetuses with at least three skeletal variations in all groups exp osed to MFs. In conclusion, the 50 Hz or 20 kHz MFs did not increase i ncidences of malformations or resorptions in CBA/Ca mice, but increase d skeletal variations consistently in all exposure groups. (C) 1998 Wi ley-Liss, Inc.