1. Plural of oestrial; a group of weak estrogenic steroid hormones produced mainly by the placenta during pregnancy, used clinically as markers of fetal health.
Usage: chiefly British spelling (American: estriols); medical/biochemistry term; typically used in plural form

Examples

• Maternal serum oestriols are measured during prenatal screening to assess fetal development.
• The levels of oestriols increase significantly during the third trimester of pregnancy.
• Abnormal oestriols levels may indicate potential chromosomal abnormalities in the fetus.
• Doctors monitor oestriols as part of the triple screen test for Down syndrome.
• Oestriols are produced primarily by the placenta and fetal liver during gestation.