Effects of hyperthermia on fetal and maternal plasma prostaglandin concentrations and uterine activity in sheep

Abstract

The exposure of pregnant sheep to high ambient temperatures (43°C) for 8 hours, sufficient to significantly elevate maternal and fetal body temperature +2.0°C (p < 0.001) and +1.9°C (p < 0.001) respectively, resulted in significant increases in PGE 2 plasma concentrations in both the maternal and fetal circulations. Plasma PGF 2α concentrations were significantly raised in the fetal circulation but not the maternal during hyperthermia. The increase in prostaglandin concentrations were correlated with the magnitude of the increase in maternal and fetal body temperature. Uterine activity also increased during hyperthermia, probably as a result of the increase in prostaglandin concentrations. We propose that increased synthesis and release of prostaglandins from the uterus and/or placenta is an adaptive response to hyperthermia, and may protect the fetus from the consequences of heat stress.