The impact of the isolated low-frequency rotating electric field (the REF) and the one combined with animal immobilisation on the "mother-placenta-fetus" system in rats with various prognostic stress resistance was studied. The research showed that on the 10th experiment day stress hormone content in the blood plasma increased in experimental rats compared to the control group; the increase degree was dependant on individual species stress-resistance. Thus, on isolated action of technogeneous rotating electric field the level of 11-oxocorticosteroids increased by 7,8 % (p > 0,05) in "active" female rats and by 71,7 %in "passive" ones. In conditions of action of combined rotating electric field with immobilization of experimental animals the level of corticosteroids increased by 63,8 % (p< 0,05) in stress-resistant rats and by 35,4 % (p < 0,05) in stress-non-resistant rats. The results of the pathomorphological study of the afterbirth and fetuses from the experimental female rats indicated that the REF leads to the structural plasenta changes, hemodynamical disturbances and are accompanied by the late fetus growth and high embrional mortality rate. The most marked functional and structural changes in the afterbirth were seen under the REF combined with animal immobilisation.