The Concentration of Oestrogens in Maternal and Foetal Blood Obtained at Caesarean Section, and the Effect of Hospitalization on Maternal Blood Oestrogen Levels

Abstract

THE pregnant woman excretes large amounts of oestrone and oestradiol and, in particular, very large amounts of oestriol in her urine (Brown, 1956); there are smaller amounts of oestrogens present in the peripheral blood of the pregnant woman (Preedy and Aitken, 1957; Aitken, Preedy, Eton and Short, 1958;Roy and Brown, 1960;Ittrich, 1960;Roy and Mackay, 1962). Earlier workers (e.g., Brown, 1957) considered that the placenta produced these large amounts of oestrogens, but other workers, in particular Diczfalusy and co-workers, suggested that oestrone and oestradiol were produced by the placenta and metabolized by the foetus to oestriol (Diczfalusy and Magnusson, 1958) or other metabolites (Diczfalusy et al., 1961). If this is so, then one might expect to find a difference in the levels of oestrogens in umbilical venous and arterial blood. Aitken et al. (1958) compared the levels in cord blood and in the maternal peripheral venous blood of two patients delivered by Caesarean section and two patients in normal labour. Other workers have published results for cord blood (Diczfalusy and Magnusson, 1958;Roy and Brown, 1960;Ittrich, 1960) but have not made a direct comparison between the levels in the mother and her foetus. The results of these previous investigations will be discussed later.The purpose of this paper is to report the results of a comparison of oestrogen levels in blood from the umbilical vein, the umbilical artery, the maternal uterine and arm vein, and also in amniotic fluid obtained from thirteen women at Caesarean section. A further object of this study was to investigate the umbilical arterial-venous difference in oestrogen levels, as this might indicate the part played by the foetus in the metabolism of the oestrogens produced 1 by the placenta. In addition, a comparison of the levels in the arm and uterine vein would give an indication of the amount of oestrogen which is transferred from the placenta to the maternal circulation. In the course of this study it became apparent that the peripheral levels, especially of oestrone, in women undergoing Caesarean section, were lower than the levels found in a series of healthy out-patients 37-41 weeks pregnant (Roy and Mackay, 1962). A further series of ten patients about to undergo Caesarean section was therefore studied in order to determine whether any drug given prior to operation could have affected the results in any way. It had previously been observed that the oestrone levels in a random series of hospital in-patients were also low. A further possibility, therefore, was that all patients in hospital had lower blood oestrogen levels than out-patients. The effect of admission to the antenatal ward of the hospital was studied, therefore, on a group of patients admitted to hospital with minor ailments. MATERIALS AND METHODBlood oestrogen determinations were performed by the method of Roy and Brown (1 960). The assays on peripheral blood, which was obtained by venipuncture of an arm vein, and on uterine venous blood were carried out in duplicate on 2...

Biochemical Tests for the Assessment of Feto-Placental Function

“…This was in agreement with the results of Macourt et al (1971), who recorded less than 12.5 % variation in patients without renal problems in similar circumstances, but differed from those of Roy (1962) who had earlier concluded that hospitalization and bed rest resulted in a fall in plasma total oestrone and total oestradiol-17,8.…”

“…Normal values were found in Rhesussensitised pregnancies and low values were noted after fetal death in utero. Values were found to rise on hospitalisation in contrast to the earlier observations of Roy (1962). Fisher-Rasmussen (1971) also used GLC to measure plasma oestriol in 15 women whose babies subsequently showed fetal asphyxia (11) or were stillborn (4).…”

Comparison of Maternal Serum and Urinary Oestrogen Determinations as Indicators of Fetal Well-Being

“…This might have been a contributing factor to the wide variations in serum oestrogen concentrations and urinary oestrogen excretion between patients The mean value for serum oestrogens in our series rose in 'normal' pregnancy from 90 nrnol/] at the 20th week to 540 at the 39th week. These values were lower than those reported for total oestrogens in serum determined by colorimetric or fluorimetric methods (Preedy and Aitken, 1957;Roy, 1962;Dubin et al, 1973;Aickin et al, 1974;Hahnel ('I al., 1974) or for total oestriol measured by radioimmunoassay (Klopper et al, 1975;Trolle et al, 1976). This difference is not surprising, as the antiserum we employed does not measure oestrogen sulphates.…”

Application of the Ittrich Extraction Procedure to the Fluorimetric Measurement of Oestrogens in Blood

“…In 1960 Roy & Brown described a method based on colorimetry by which it was possible to measure the oestrogen content of blood from a pregnant woman and from the foetus (Roy & Mackay, 1962;Roy, 1962), but the method was not sufficiently sensitive to measure accurately the very smah amount of oestrogens present in the blood of non-pregnant individuals. The present communication describes a modifica¬ tion of their method in which the more sensitive fluorescence procedure replaces the Kober colour reaction.…”