Suspected of damaging fertility.
Octamethylcyclotetrasiloxane administered to rats by whole body inhalation at concentrations of
500 and 700 ppm for 70 days prior to mating, through mating, gestation and lactation resulted in
decreases in live litter size. Additionally, increases in the incidence of deliveries of offspring
extending over an unusually long time period (dystocia) were observed at these concentrations.
Statistically significant alterations in these parameters were not observed in the lower
concentrations evaluated (300 and 70 ppm). In a previous range-finding study, rats exposed to
vapor concentrations of 700 ppm had decreases in the number of implantation sites and live litter
size. The significance of these findings to humans is not known. [Octamethylcyclotetrasiloxane]