UNCONJUGATED OESTETROL IN PLASMA IN RESPONSE TO AN INTRAVENOUS LOAD OF DEHYDROEPIANDROSTERONE SULPHATE (DHAS) IN UNCOMPLICATED AND COMPLICATED HUMAN PREGNANCY

Abstract

ABSTRACT A non-chromatographic radioimmunoassay for estimation of unconjugated oestetrol in plasma from pregnant women is described. The antiserum has a high specificity to oestetrol. The technical procedure is simple and rapid. Only small amounts of plasma (0.2–0.4 ml) are needed for the analysis. The method has been applied to the measurement of oestetrol in plasma from pregnant women before and after an intravenous injection of 50 mg DHAS. In women with uncomplicated pregnancies a rise of plasma oestetrol was found 60 min after the injection. From 120 to 360 min there was a plateau level, at 600 min a decrease from this level was observed. No changes in the oestetrol response were found with advancing gestational age from the 33rd to the 40th week of pregnancy. A great spread in the individual responses were recorded. Patients with pre-eclampsia and intrauterine growth retardation had a tendency to a lower increase and patients with diabetes a tendency to a higher increase of plasma oestetrol after the DHAS administration. From the data obtained it is concluded that the increase of plasma oestetrol after an intravenous injection of DHAS in most cases is secondary to the increase of plasma oestradiol. The results suggest that measurement of unconjugated oestetrol in plasma after an intravenous load of DHAS is no safe way to assess foetal wellbeing. In women with intrauterine growth retardation (IUGR) the simultaneous measurement of plasma oestradiol and oestetrol after an injection of DHAS indicates a possibility to distinguish placental from foetal causes of this syndrome.