[Fetal hypoxia--etiology and pathophysiology of hypoxic damage].

In current perinatology, the prevention of hypoxic damage to the organs, brain in particular, is given special emphasis. The causes of fetal hypoxia include maternal (preuterine), intrauterine, umbilical, placental and fetal causes. Hypoxia and hypoxic lesions occur prenatally in about 80%, and perinatally in 10-20% of cases. Hypoxia/ischemia induce cellular and subcellular responses in the fetal brain. Some of these are membraneous phenomena such as potassium channel activation, enhanced release of excitoxic amino acids aspartate and glutaminate, activation of NMDA receptors, transmembranous calcium ion influx, and membranous lipid peroxidation. Cytosolic events include the formation of free oxygen radicals, release of eicosanoids, prostaglandins, leukotriens and cytokines, enzyme activation, and gene induction.