Table 2.
Reproductive Performance, Prenatal Mortality, and Fetal and Placental Sizes in Rats Exposed to 20 or 60 kHz Magnetic Fields
| 20 kHz, 0.2 mT(rms) Magnetic field | 60 kHz, 0.1 mT(rms) Magnetic field | |||||||
|---|---|---|---|---|---|---|---|---|
| Experiment 1 | Experiment 2 | Experiment 1 | Experiment 2 | |||||
| Parameter | Sham-exposed | MF-exposed | Sham-exposed | MF-exposed | Sham-exposed | MF-exposed | Sham-exposed | MF-exposed |
| Examined dams | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 |
| Corpora lutea per dam | 16.6 ± 1.8a | 15.4 ± 2.1* | 15.3 ± 2.2 | 15.2 ± 2.3 | 16.2 ± 1.9 | 16.1 ± 2.5 | 16.2 ± 2.7 | 17.3 ± 2.5 |
| Implants per dam | 15.1 ± 1.2 | 14.4 ± 1.6 | 14.4 ± 1.5 | 14.1 ± 1.9 | 14.1 ± 1.9 | 14.2 ± 1.6 | 14.8 ± 2.1 | 15.2 ± 1.3 |
| Dams with preimplantation losses/Examined dams | 16/25 | 15/25 | 10/25 | 10/25 | 20/25 | 22/25 | 13/25 | 18/25 |
| Preimplantation losses per dam (%) | 8.8 ± 8.0 | 6.3 ± 6.5 | 5.6 ± 8.1 | 6.8 ± 12.9 | 12.5 ± 12.4 | 10.7 ± 7.0 | 7.9 ± 10.6 | 10.8 ± 9.2 |
| Postimplantation losses during early pregnancyb | 9 | 7 | 10 | 7 | 8 | 11 | 9 | 10 |
| Postimplantation losses during middle pregnancyc | 0 | 3 | 0 | 0 | 2 | 0 | 0 | 3 |
| Postimplantation losses during late pregnancyd | 0 | 0 | 0 | 0 | 2 | 0 | 2 | 0 |
| Dams with postimplantation losses/Examined dams | 7/25 | 8/25 | 9/25 | 7/25 | 9/25 | 9/25 | 8/25 | 10/25 |
| Postimplantation losses per dam (%) | 2.3 ± 4.0 | 2.8 ± 4.5 | 2.7 ± 3.9 | 1.9 ± 3.1 | 3.3 ± 6.2 | 3.1 ± 4.8 | 2.7 ± 4.3 | 3.4 ± 4.9 |
| Dams with implantation losses/Examined dams | 20/25 | 18/25 | 13/25 | 15/25 | 23/25 | 22/25 | 20/25 | 20/25 |
| Total implantation losses per dam (%) | 11.0 ± 7.8 | 8.9 ± 7.6 | 8.1 ± 9.3 | 8.7 ± 12.6 | 15.6 ± 12.2 | 13.5 ± 8.1 | 10.6 ± 9.7 | 13.7 ± 10.5 |
| Live fetuses | 368 | 349 | 349 | 345 | 340 | 345 | 360 | 368 |
| Dams with live fetuses/Examined dams | 25/25 | 25/25 | 25/25 | 25/25 | 25/25 | 25/25 | 25/25 | 25/25 |
| Live fetuses per litter (%) | 89.0 ± 7.8 | 91.1 ± 7.6 | 91.9 ± 9.3 | 91.3 ± 12.6 | 84.4 ± 12.2 | 86.5 ± 8.1 | 89.4 ± 9.7 | 86.3 ± 10.5 |
| Live fetuses per litter | 14.7 ± 1.2 | 14.0 ± 1.6 | 14.0 ± 1.5 | 13.8 ± 1.8 | 13.6 ± 2.0 | 13.8 ± 1.7 | 14.4 ± 1.8 | 14.7 ± 1.5 |
| Male fetuses/Female fetuses | 198/170 | 175/174 | 195/154 | 183/162 | 175/165 | 179/166 | 158/202 | 190/178 |
| Male to fetuses per litter (%) | 53.6 ± 12.8 | 49.9 ± 15.0 | 55.9 ± 14.0 | 53.0 ± 15.4 | 50.9 ± 12.4 | 52.1 ± 10.6 | 43.7 ± 10.1 | 51.7 ± 10.5* |
| Body weight of male fetus per litter (g) | 3.91 ± 0.36 | 3.83 ± 0.25 | 3.85 ± 0.22 | 3.79 ± 0.22 | 3.87 ± 0.23 | 3.78 ± 0.23 | 3.92 ± 0.26 | 3.93 ± 0.20 |
| Body weight of female fetus per litter (g) | 3.70 ± 0.39 | 3.59 ± 0.25 | 3.64 ± 0.23 | 3.62 ± 0.22 | 3.70 ± 0.18 | 3.62 ± 0.23 | 3.71 ± 0.28 | 3.68 ± 0.22 |
| Low-body-weight (<2.5 g) fetuses/Litters | 1/1e | 1/1 | 1/1 | 0/0 | 3/3 | 1/1 | 2/2 | 3/3 |
| Placental weight of male fetus (mg) | 475 ± 56 | 470 ± 49 | 455 ± 48 | 472 ± 61 | 450 ± 38 | 462 ± 53 | 463 ± 45 | 458 ± 49 |
| Placental weight of female fetus (mg) | 459 ± 74 | 439 ± 47 | 445 ± 55 | 460 ± 62 | 431 ± 43 | 428 ± 42 | 438 ± 40 | 439 ± 55 |
MF, magnetic field.
a
Mean ± SD.
b
Implantation sites on the endometrium or placental remnants smaller than 3 mm in diameter.
c
Placental remnants larger than 3 mm in diameter or dead fetuses smaller than the placental diameter.
d
Macerated fetuses or dead fetuses larger than the placental diameter.
e
Total number of low-body-weight fetuses/total number of litters with at least one low-body-weight fetus.
*
Significantly different from concurrent sham-exposed group (p<0.05).