Effects of heat--stress in rats: Critical period and reduced survival of post-implantation heat-stress inducted in early gestation.

ABSTRACT

High ambient temperature (34.4 C degrees and 60-65% relative humidity (RH) did not affect foetal survival when bred female rats were exposed between day-8 and -18 (Day-0=day of breeding). Heat-stress at this intensity given on day-0 was critical for embryonic and/or foetal survival rate and more so, if the ambient temperature was increased to 36.6 C degrees and 70-75% RH than on day-1. Postimplantation foetal survival was reduced due to heat-stress given only during early gestation period.