1. Plural of estriol; a weak estrogen hormone produced mainly during pregnancy, found in high concentrations in maternal urine and used as a marker in prenatal screening.
Usage: medical/scientific term; typically used in plural form; common in obstetrics and prenatal care contexts

Examples

• Estriols are measured in maternal serum during the second trimester as part of prenatal screening.
• High levels of estriols in urine can indicate a healthy pregnancy.
• The doctor ordered tests to check estriol levels as part of the routine prenatal panel.
• Estriols are one of three markers used in the triple screen test for Down syndrome.
• During pregnancy, estriol production increases significantly in the placenta.