Studies of gas tensions, pH, and viscosity in amniotic fluid of sheep

Gas tensions and pH of the amniotic fluid in sheep were compared to those of umbilical cord blood. Observations also were made on the relationship of viscosity of the amniotic fluid to the survival of the fetus. The Po2 was higher in the amniotic fluid than in the umbilical artery but lower than in the vein. The Pco2 was consistently higher and the pH consistently lower than in either of these vessels. A highly viscous fluid was uniformly associated either with failure to survive or with severe neonatal distress.