Effect of changes in ambient temperature on maternal plasma and allantoic fluid from chronically catheterised ewes during the last two months of pregnancy.

At ambient temperatures of 17-22 degrees C hypoglycaemia (plasma glucose levels smaller than 45 mg/100 ml) in pregnant sheep was associated with rising potassium concentrations in allantoic fluid, while at temperatures below 12 degrees C glucose levels were higher and coincided with falling potassium values. It is suggested that the fetus is sensitive to changes in maternal glucose balance induced by variations in anbient temperature, and this indicates the need to consider the environmental temperature in metabolic studies of fetal sheep.