Unconjugated Estriol and Cortisol in Maternal and Cord Serum and Amniotic Fluid in Normal and Abnormal Pregnancy

Abstract

Study was made of unconjugated estriol (E) by radioimmunoassay and cortisol (C) by competitive protein-binding assay in the maternal serum (Mat), mixed cord blood (Cord), and amniotic fluid (AF) from 50 pregnancies, 37 or more weeks' gestation (30 normal women, 9 insulin-dependent diabetics; 8 with chronic stress: precclampsia, eclampsia; 3 sets of uncomplicated twins). The normal patients' results were suggestive that Cord E and C were derived from a common precursor or fetal organ activity (r=0.382, P<0.05) and that Mat E, which correlated with Cord E (r=0.432, P<0.05), reflected fetoplacental metabolism. Within 1 hour of delivery, Mat E dropped to<2.0 ng/ml. Insulin-dependent diabetics had values similar to those in the normal population. In chronically stressed patients, the results suggest that stress causes fetal C production to increase relative to E. The Mat E (mean value, 6.18 ±1.23 ng/ml) was significantly less than normal (P<0.01), while the Cord C (mean value, 35.4 ± 4.5 yug/dl) was greater than in the normal baby (P<0.01). Twin pregnancies demonstrated elevated Mat E, but individual Cord E approximated the normal singleton. Paired sample mean ratios of E and C in the various compartments were utilized to differentiate groups of patients. The Mat E/AF E and Mat C/AF E gave meaningful differences that could be clinically useful because of the availability of sampling. The biosynthetic pathways of E and C, the metabolic and compartmental interrelationships, and the control mechanisms are discussed and related to the data.