Free Estriol ELISA

Estriol (also oestriol) is one of the three main
estrogens produced by the human body. It is only
produced in significant amounts during pregnancy as
it is made by the fetus. During pregnancy the production of estriol depends
on an intact maternal-placental-fetal unit. Fetal- placental production of estriol leads to a progressive
rise in maternal circulating levels reaching a late- gestational peak several orders of magnitude greater
than non-pregnant levels. In the maternal circulation,
estriol undergoes rapid conjugation in the liver
followed by urinary excretion with a half-life of ~20
minutes. Since normal estriol production depends on
an intact maternal-placental-fetal circulation and
functional fetal metabolism, maternal estriol levels
have been used to monitor fetal status during
pregnancy, particularly during the third trimester.
DHEA is produced by the adrenal cortex of the fetus,
this is converted to estriol by the placenta.
If levels are abnormally low in a pregnant woman, this
may indicate a problem with the development in the
child. Levels of estriol in non-pregnant women do not
change much after menopause, and levels are not
significantly different from levels in men.