To study the hypothesis that magnetic fields enhance the implantation of embryos which would normally rejected (i.e. embryos which are not sufficiently matured to implant after reaching the uterus). For this purpose female rats were exposed to magnetic fileds during the early pregnancy period and pre-implantated and implanted embryos were collected from oviducts and uteri, respectively.
Female rats were continuously exposed 24 h/day in the early period of pregnancy (i.e. up to 176 h). Dams were killed and examined both during light and dark periods (70, 80, 94, 104, 118, 128, 142, 152, 166, and 176 h after ovulation).
Exposure duration: 24 h/day from day 0 of pregnancy until at least 70 h up to 176 h after ovulation
|Setup||two pairs of Helmholtz coils in wooden frames; coils with a cross section of 0.425 x 1.205 m, 0.155 m apart; horizontal distance between coil pairs 0.485 m; two cages inside each coil; for 13 µT coils with 1 turn; for 130 µT coils with 10 turns|
|Sham exposure||A sham exposure was conducted.|
|magnetic flux density||13 µT||effective value||-||-||-|
|magnetic flux density||130 µT||effective value||-||-||-|
|magnetic field strength||100 A/m||-||-||-||-|
|magnetic field strength||10 A/m||-||-||-||-|
|magnetic flux density||48 µT||minimum||measured||-||e: geomagnetic flux density with EMF exposure: 48 - 55 µTd: geomagnetische Flußdichte bei EMF Exposition: 48 - 55 µT|
|magnetic flux density||45 µT||minimum||measured||-||e: geomagnetic flux density without EMF exposure: 45 - 50 µTd: geomagnetische Flußdichte ohne EMF Exposition: 45 - 50 µT|
Magnetic field exposure did not alter the mean total number of implantations. Nocturnal melatonin levels were decreased by 38 and 34% at 100 and 10 A/m, respectively. Serum levels of progesterone and estradiol were not significantly changed. Whilst early implantation period, the cytosolic ratio of estrogen- to progesterone receptors was found to be decreased at 100 A/m. Whereas the nuclear ratio of estrogen-/progesterone receptors was decreased in both exposure groups. 15 and 19% of the embryos at 100 and 10 A/m were yet morulae and not implanted.
The authors summarize, that magnetic field exposure do not impair implantation in rats although there may be some borderline changes in embryonic development and endocrine parameters.