Plasma Oestriol in Pregnancy

Abstract

Summary Total plasma oestriol in pregnancy was estimated by a competitive protein binding method. The advantages of the measurement of plasma oestriol levels over the 24‐ or 48‐hour urinary oestriol assays are discussed. The pattern of plasma oestriol levels in the third trimester of pregnancy was investigated in over 400 healthy women and in general a uniform increase was found from the 28th week until term. Diurnal variation was found to be present, but this did not preclude the use of the method for assessing the feto‐placental unit. Exercise and meals had a minimal effect on the oestriol levels. Following delivery the level decreased sharply to reach, within four hours, one‐half that found just prior to delivery.

Variability of Total Plasma Oestriol in Late Human Pregnancy

“…The fact that there was no difference in levels of oestriol in plasma in relation to meals supports the view that diet does not influence the level of oestriol. This finding has also been reported by Macourt et al (1971).…”

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.…”

“…Subsequently these workers were unable to confirm these results in another group of patients (Levitz et al, 1974). A small diurnal variation (approximately 10%) was noticed in three out of five patients by Macourt et al (1971) who claimed that it was not great enough to preclude the use of the method for clinical assessment of the fetoplacental unit. A lack of diurnal variation has also been reported for plasma unconjugated oestradiol-17,8 (Tulchinsky and Korenman, 1971) and unconjugated oestriol ) and for plasma total oestriol (Masson and Wilson, 1972).…”

“…Day-to-day variations of between 5 % and 13% (CV) have been reported for total oestriol (Macourt et al, 1971;Masson and Wilson, 1972), for unconjugated oestradiol-17,8 (Chan and Klopper, 1974;Klopper and Shaaban, 1974), and for conjugated oestradiol-17,8 (Chan and Klepper, 1974). These variations are lower than those generally reported for urinary oestrogens.…”

A Simplified Radioimmunoassay of Human Gravid Plasma Estriol

“…However, because urinary E3 especially conjugated E3 is influenced by diurnal and positional variations and require 24hr specimens, various conditions must be stipulated in order to establish a criteria for clinical significance of E3 in urine (Macourt et al, 1971;Bird and Reeves, 1969;Stewart et al, 1970;Selinger and Levitz, 1969;Ricky, 1966). In contrast, plasma unconjugated E3 increases similarly to urinary E3 and is not affected as easily by varying conditions.…”