Urinary Excretion of Corticosteroid C-21 Sulfates During Human Pregnancy1

Abstract

Several steroids of the pregn-4-ene-21-yl sulfate series such as cortisol, cortisone and corticosterone sulfates were previously quantified in the urine of newborn infants, and their output found to be quantitatively comparable to that of tetrahydrocortisone glucuronide. To determine the possible origin of these conjugates, their excretion was measured and compared in nonpregnant and pregnant women at midterm, term and following parturition. Double isotope assays were employed to characterize and quantify all urinary steroids, the main ones being the sulfates of cortisol, cortisone, corticosterone, 11-dehydrocorticosterone and the glucuronides of tetrahydrocortisone and tetrahydrocortisol. At term, one observed a marked increase of the urinary excretion of these conjugates above values obtained for nonpregnant subjects, while following parturition their urinary output fell within the range observed for nonpregnant subjects. There was no conspicuous difference in the urinary excretion of the glucuronides of tetrahydrocortisol and tetrahydrocortisone among these different groups of women. The data provide indirect evidence that, during the last trimester of pregnancy, these steroid sulfates originate mainly from the fetus. Following birth their urinary output by the newborn reflects processes which were in part initiated in utero.