Short-term effects of different thermal conditions during uteroplacental ischaemia on fetal growth of Sprague-Dawley rats.

The purpose of the present study was to investigate the short-term effect of various body temperatures on fetal growth during uteroplacental ischaemia. Under mild hyperthermia (n = 6), normothermia (n = 6) and hypothermia (n = 6), a 30-min period of ischaemia was induced in Sprague-Dawley rat dams by clamping the uterine arteries of one uterine horn at 17 days of gestation, leaving the other horn undisturbed. Three days later, the bodyweight of the pups, and the weights of the brains, livers and placentas were compared using the Mann-Whitney U-test. Fetal bodyweight, organ and placental weights were significantly reduced in the uterine horns subjected to ischaemia under the conditions of mild hyperthermia and normothermia (P<0.05), but not with mild hypothermia, compared with the weights in undisturbed uterine horns. It was concluded that both mild hyperthermia and normothermia during ischaemia retard the growth of late-gestation rat pups, in contrast to the sparing effect of mild hypothermia.