Observations on the variability of plasma estriol

Area of Science:

• Reproductive Endocrinology
• Maternal-Fetal Medicine
• Clinical Chemistry

Background:

• Estriol is a key hormone in pregnancy, reflecting fetal adrenal function.
• Monitoring estriol levels can indicate fetal health status.
• Variability in estriol measurements needs to be understood for accurate clinical interpretation.

Purpose of the Study:

• To assess the daily variability of total and unconjugated plasma estriol.
• To determine the reliability of estriol measurements in the late third trimester of pregnancy.

Main Methods:

• Plasma samples were collected daily from 9 pregnant women.
• Measurements were performed over an 8-day period during the 38th week of gestation.
• Total and unconjugated estriol concentrations were quantified.

Main Results:

• The average coefficient of variation for total plasma estriol was 15.0%.
• The average coefficient of variation for unconjugated plasma estriol was 16.5%.
• These coefficients suggest moderate daily variability in estriol levels.

Conclusions:

• Daily estriol measurements exhibit moderate variability in late pregnancy.
• The observed variability is comparable for both total and unconjugated estriol.
• These findings support the feasibility of daily estriol monitoring in clinical practice.