[Parameters of maternal oxygen transport in risk pregnancies]

Fetal oxygen supply depends on the one hand on placental perfusion and on the other on maternal and fetal oxygen transport parameters. In the study reported here the maternal oxygen transport parameters, such as the O2 half-saturation pressure P50 (mmHg) and the factors influencing it (2, 3-DPG, ATP, pH) were studied in high-risk pregnancies in comparison with a control group of normal pregnancies. A total of 112 patients at the Department of Gynecology and Obstetrics of the Rhine-Westphalian Technical University in Aachen were examined. All calculations were done with the BMDP static analysis system. Using the Mann-Whitney test, no location differences in the various parameters were detected at the level alpha = 0,05 between to group of patients with EPH gestosis and the control group. The same results were obtained when patients with placental insufficiency were compared with the control group. In contrast, a significant shift in location in oxygen transport was detectable in patients in whom there was an imminent danger of premature birth. In such cases it must be assumed that the fetus is at risk. After at least two days' intravenous administration of Fenoterol the possibility of a transient deficiency of fetal oxygen supply due to the change in the maternal oxygen transport parameters must be considered, since it cannot be assumed that there will be a compensatory increase in placental perfusion under Fenoterol. With peroral tokolysis the oxygen supply to the fetus is not impaired as far as maternal oxygen transport parameters are concerned.