Correlation between first morning sample and 24-hour urinary estriol excretion.

Area of Science:

• Obstetrics and Gynecology
• Clinical Chemistry
• Maternal-Fetal Medicine

Background:

• Estriol (E3) is a key urinary biomarker in high-risk pregnancies.
• Accurate estriol monitoring is crucial for assessing fetal well-being.
• 24-hour urine collection is the standard for estriol excretion measurement.

Purpose of the Study:

• To evaluate the correlation between morning urine estriol concentration and total 24-hour estriol excretion in high-risk pregnancies.
• To determine if morning urine estriol can reliably predict 24-hour estriol levels.

Main Methods:

• Correlation analysis was performed on paired urine samples.
• 170 pairs compared morning samples with the previous 24-hour collection.
• 110 pairs compared morning samples with the following 24-hour collection.

Main Results:

• A statistically significant correlation was observed between morning and 24-hour estriol levels.
• The magnitude of this correlation was modest.
• Mean estriol values differed significantly between morning and 24-hour samples.
• Morning estriol concentrations exhibited greater variability than 24-hour samples.

Conclusions:

• While morning urine estriol concentration correlates with 24-hour excretion, it is not a sufficiently precise substitute for 24-hour monitoring in high-risk pregnancies.
• The increased variability and differing mean values of morning samples limit their predictive value.
• Clinicians should continue to rely on 24-hour urine collections for accurate estriol assessment.