Embryotoxic and teratogenic studies of phosphamidon in Swiss albino mice.

Phosphamidon, an organophosphate pesticide, is little known for its possible effects on mammalian conceptus. The present investigation was carried out to evaluate its embryotoxic and teratogenic effects on Swiss albino mice. Female mice of similar age and weight were divided into four experimental groups. The animals of groups I and II received 15 and 35 ppm phosphamidon ad libitum, respectively, during the entire gestational period, that is, from days 1 to 18. Groups III and IV were treated before mating with 35 ppm phosphamidon for 30 and 60 days, respectively, and the treatment was continued during pregnancy up to the 18th day. The autopsies were performed on the 18th day of gestation, and routine teratological observations were made. The lower dose did not produce significant effects. The higher dose reduced the number of implants, litter size, and foetal weight and increased the resorption of embryos when administered for 30 days prior to mating. Exposure to the pesticide for 60 days prior to mating and during gestation, however, did not produce significant effects. It appears that the mice probably developed some resistance to the pesticide, when exposed for such a long duration.