Screening in Pregnancy with Unconjugated Estriol Compared with total Estriol

Abstract

An obstetric population was screened ‘blind’ by measuring unconjugated estriol (ucE₃) and total estriol (tE₃) in serum. The purpose was firstly to ascertain the predictive values of ucE3 for the prediction of low birth weight and distressed neonates (perinatal deaths included), and secondly to compare the predictive values of ucE₃ and tE₃. The main material consisted of 1018 singleton pregnancies with known term, who would not have undergone estriol (E₃) measurement had it not been for this investigation. The study was carried out prospectively, and the obstetricians had no knowledge of the E₃ values in the screened pregnancies. When at least one of the ucE₃ values was low, the risk of having a small for gestational age (SGA) infant was 22%. Low tE₃ implied a 27% risk. When both were low, the risk of a SGA infant was 54%. The percentages of SGA infants found were 18, 19, and 12%, when ucE₃, tE₃, or both respectively, were low. ucE₃ does not appear to be superior to tE₃. From the predictive values found in this study, screening of a total obstetric population with ucE₃ and/or tE₃ cannot be recommended.

Key Words:

• Pregnancy screening
• serum estriol