Reliability of antenatal testing: estriol levels versus nonstress testing

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Perinatal Diagnostics

Background:

• High-risk pregnancies require accurate antenatal surveillance to detect fetal compromise.
• Traditional methods include plasma estriol levels and fetal heart rate (FHR) monitoring.
• Evaluating the reliability of different antenatal tests is crucial for clinical decision-making.

Purpose of the Study:

• To compare the efficacy of nonstress testing (NST) with beat-to-beat FHR variability assessment against serial unconjugated plasma estriol determinations.
• To determine which antenatal test is more reliable in identifying fetal compromise in high-risk pregnancies during the third trimester.

Main Methods:

• Prospective follow-up of 334 high-risk pregnant patients in their third trimester.
• Antenatal fetal heart rate (FHR) evaluation including nonstress testing (NST) and beat-to-beat variability assessment.
• Serial determinations of unconjugated plasma estriol levels.

Main Results:

• Nonstress testing (NST) demonstrated higher reliability in assessing fetal compromise compared to estriol analysis.
• NST/beat-to-beat variability accurately identified fetal jeopardy in over 45.0% of at-risk fetuses.
• Abnormal estriol values accurately predicted jeopardy in only 22.8% of cases.

Conclusions:

• Nonstress testing (NST) with beat-to-beat FHR variability assessment is a more accurate predictor of fetal jeopardy than plasma estriol levels.
• Abnormal NST findings, particularly loss of beat-to-beat FHR variability, should take precedence in antenatal surveillance protocols for high-risk obstetric patients.
• These findings support the enhanced utility of FHR monitoring over biochemical markers for timely detection of fetal distress.