Increased Urinary Estriol Excretion without Change in Blood Estriol Concentration Resulting from Bed Rest in the Third Trimester of Pregnancy in the Human

Abstract

Placing normally pregnant women at bed rest during the third trimester significantly increased the amount of total estrogen excreted into the urine to 122% of the control value, but the concentration of total serum estriol was not significantly altered. Estriol biosynthesis, secretion, conjugation, metabolism, and excretion are regulated by many poorly understood factors, but for purposes of clinical evaluation of the well-being of the infant, bed rest would appear to be another circumstance under which more reliable information can be obtained by blood instead of urine analysis.