Oxygen dissociation curves of the bloods of maternal and fetal goats as they exist in vivo.

Oxygen dissociation curves of maternal and fetal bloods prepared in vitro have been described in several species including the goat.' The use of recent polarographic methods for measuring oxygen tension in blood avoids any possible alteration in oxygen affinity of the blood during equilibration in tonometers and could theoretically result in more accurate maternal and fetal oxygen dissociation curves. Any changes would be reflected in estimates of the average oxygen pressure difference between maternal and fetal blood in the placenta2 and in measurements of the permeability of the placenta to oxygen. In order to further quantitate the supply of oxygen to the goat fetus in utero, we have, therefore, investigated the relationship between maternal and fetal oxygen dissociation curves in zivo.