Meschia G
J Reprod Med. 1985 Apr;30(4):308-11.
The supply of O2 to fetal tissues depends upon a balance between factors that favor and hinder fetal oxygenation. Experiments in sheep have demonstrated that high rates of placental perfusion, high O2 affinity of fetal red cells and high rates of perfusion in fetal tissues compensate for an ineffective placental exchange system and for the circulatory arrangement by which fetal arterial blood is formed by mixing oxygenated umbilical venous blood with deoxygenated systemic venous blood. Under normal physiologic conditions the balance of the factors that influence fetal oxygenation provides the fetal lamb with an oxygen supply approximately twice the minimum level necessary to sustain fetal life.
向胎儿组织供应氧气取决于促进和阻碍胎儿氧合的各种因素之间的平衡。在绵羊身上进行的实验表明，高胎盘灌注率、胎儿红细胞的高氧亲和力以及胎儿组织的高灌注率弥补了无效的胎盘交换系统以及胎儿动脉血由含氧的脐静脉血与脱氧的体静脉血混合形成的循环结构。在正常生理条件下，影响胎儿氧合的各种因素的平衡为胎羊提供的氧气供应量约为维持胎儿生命所需最低水平的两倍。
