DIURNAL-VARIATIONS IN UNCONJUGATED AND TOTAL PLASMA ESTRIOL LEVELS IN LATE NORMAL-PREGNANCY

  • 1 January 1979
    • journal article
    • research article
    • Vol. 53  (5) , 623-626
Abstract
Diurnal variations in plasma unconjugated and total estriol [E3] were assessed in 11 3rd trimester subjects with uncomplicated pregnancies. Commercially available 125I-labeled radioimmunoassay kits were used. Total plasma E3 reach a nadir during sleeping hours (400 and 700 h) which exceeds the episodic fluctuations seen from day to day or during a given 90 min period. Plasma unconjugated E3 fluctuations over 24 h did not significantly exceed the previously reported episodic fluctuation of 15.6 .+-. 8.2%. The data are interpreted as showing no circadian rhythm, but reflecting, in the case of total plasma E3, an effect of improved renal clearance during hours of rest. Plasma unconjugated E3 emerges as the test of choice in the monitoring of high-risk pregnancies.