Urine estriol or total estrogens. Estriol is an estrogenic compound produced by the placenta from precursors derived from fetal adrenal cortex and fetal liver. Newly synthesized estriol is unconjugated; therefore, unconjugated estriol represents a product of the entire fetoplacental unit. The unconjugated estriol reaches maternal serum (where it has a half-life of about 20 minutes) […]