产品描述:
Estriol, a metabolite of 17β-estradiol and a major estrogen produced during pregnancy, has historically been used as an indicator of fetal well-being. In the final weeks before parturition, estriol levels increase significantly. In a longitudinal study in healthy pregnant women, total plasma estriol levels increased from 10 weeks gestation to approximately 150 ng/ml at week 38.{7767} 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.{7766} In the 1960s and 1970s plasma and urine were used to measure estriol. However, saliva contains primarily unbound and unconjugated estriol, the biologically active form of the hormone, and therefore is currently a commonly used biological fluid for monitoring estriol levels.{7766,7799} Plasma levels of estriol in males and non-pregnant females is less than 2 ng/ml.{7647}