Estriol is a metabolite of estradiol and a major estrogen produced in the later stages of pregnancy. In a longitudinal study in healthy pregnant women, total plasma estriol levels increased from <10 ng/ml at 8-10 weeks gestation to approximately 150 ng/ml at week 38.1 The majority of the estriol synthesized in the later stages of pregnancy originates from fetal dehydroepiandrosterone sulfate (DHEAS) and serves as a direct marker of fetal adrenal gland activity.2 Saliva contains primarily unbound and unconjugated estriol and is commonly used for monitoring estriol levels.2,3 Plasma levels of estriol in males and non-pregnant females is less than 2 ng/ml.4
1
Peter, M., Dörr, H.G., and Sippell, W.G. Changes in the concentrations of dehydroepiandrosterone sulfate and estriol in maternal plasma during pregnancy: A longitudinal study in healthy women throughout gestation and at term. Horm Res42278-281(1994).
2
Goodwin, T.M. A role for estriol in human labor, term and preterm. Am J Obstet Gynecol180S208-S213(1999).
3
Voss, H.F. Hormonal pathways of preterm birth. Am J Obstet Gynecol180S226-S231(1999).
Peter, M., Dörr, H.G., and Sippell, W.G. Changes in the concentrations of dehydroepiandrosterone sulfate and estriol in maternal plasma during pregnancy: A longitudinal study in healthy women throughout gestation and at term. Horm Res42278-281(1994).
Goodwin, T.M. A role for estriol in human labor, term and preterm. Am J Obstet Gynecol180S208-S213(1999).
Voss, H.F. Hormonal pathways of preterm birth. Am J Obstet Gynecol180S226-S231(1999).