In utero and lactational exposure to fenvalerate disrupts reproductive function in female rats

Fenvalerate is a synthetic pyrethroid insecticide used in agriculture and domestic insect control. Some studies have proposed that it may act as an environmental estrogen; other studies suggest possible genotoxicity in germ cells. This study aimed to evaluate the effects of fenvalerate on the female reproduction in rats whose mothers were exposed during gestation and lactation. Pregnant Wistar rats were exposed to fenvalerate (40 mg/kg) or corn oil (vehicle) orally from gestational day 12 until the end of lactation. The dose selection was based on previous studies, whereas this was considered an effective dose. Results showed decreases in ovarian weight, pre-antral follicles and corpora lutea at PND 75 and an increase in the resorption number, when fertility test was performed at PND 80. Under some experimental conditions, fenvalerate may impair reproductive development of female offspring, manifested as reduced fecundity and ovulation number, resulting from the impairment in corpora lutea counting.