Intrauterine Ischemia 1

Abstract

Interference with its oxygen supply is a major risk to the fetus during intrauterine life. Several important factors are concerned in maintaining the supply of oxygen to the fetus (maternal plasma volume expansion, dilated uterine arteries, low maternal hematocrit and viscosity and high cardiac output). All those factors govern the amount of oxygen reaching the fetus and disease processes of many kinds may interfere (pre-eclampsia, intrauterine growth retardation, Oligohydramnion). Garn et al. (1981), Sagen et al. (1984), and Murphy et al. (1986) demonstrated the potentically morbidigenic effect of high hematocrit and elevated red cell aggregation. The frequencies of perinatal death, low birth weight and abnormalities of fetal heart rates were higher with hematocrit above 38% or/and red cell aggregation above 28 (-). By contrast, a decreasing hematocrit is associated with improved pregnancy- and fetal outcome. We have used plasma volume expansion therapy with hydroxyethylstarch 200/0.5, 10% in acute and chronic situations with fetal hypoxia. Plasma volume expansion leads to an increase in maternal and fetal cardiac output and improves the placental blood flow. We conclude that the presence of a high hematocrit and red cell aggregation should alert the obstetricans to the increased perinatal risk.