Abstract: Objective An instrument of power frequency electromagnetic fields, applicable for an animal model with rats as experimental subjects, will be designed to evaluate risk of the damage on reproductive functions under low frequency electromagnetic field exposure. Method The rats were exposed to the magnetic field at certain intensity for some time. Some parameters of reproductiue function were measured including plasma levels of steroid hormones, estrous cycle, and the numbers and development status of the offspring in females, and weight of the testis and epididymis, sperm density, the proportion of motile sperms, and sperm plasma membrane integrity. Results The study found that one month exposure of 1mT electromagnetic field, 8hours daily, initiated at the age of 4 weeks didn’t induced significant change in the secretion of hormones and fertility in females, only increased estrus frequency, in the power frequency electromagnetic field at 1mT, and with daily exposure time of 8 hours, for a month since the beginning at age of 4 weeks, the grown adult female rats have not shown a significant change in the secretion of hormones and fertility to bear future generations, and only estrus frequency increased. two month exposure of 2mT electromagnetic field, 12hours daily, initiated at the age of 8 weeks induced the decline of sperm motility of males.

Key words: Frequency electromagnetic field, Rats, Fertility