E3 is the major estrogen produced by the placenta during pregnancy. uE3 passes through the placenta into the mother's bloodstream and quickly degrades to glucuronides and sulfate derivatives for excretion. Determination of serum uE3 levels can help to assess the placenta - fetal unit function, it a...

Human chorionic gonadotropin (hcg) is a glycoprotein secreted by trophoblast cells of the placenta and consists of both α- and β-subunits. hCG enters the maternal blood after fertilization and rapidly proliferates until the 8th week of pregnancy, then the concentration slowly decreases until the 1...

AFP is a protein mainly produced by fetal liver with a molecular weight of about 68KD. When pregnant women with Down Syndrome fetuses, maternal Serum AFP levels are about 23% lower than that of normal pregnant women, however, we do not yet know the cause of the decrease of AFP level in patients with...