Efficacy of Standard Biophysical Tests in Assessing Fetal Oxygenation Status

Timely recognition of fetal oxygenation disorders is essential to prevent irreversible injury. Cardiotocography (CTG) and biophysical profile (BPP) are widely used for fetal surveillance, yet their diagnostic and predictive performance relative to umbilical artery (UA) pH and neonatal outcomes warrants further evaluation. This study assessed the efficacy of CTG and BPP in predicting fetal acidosis and a low one-minute Apgar score (AS) and examined their value for identifying fetal hypoxia and asphyxia.

We conducted a retrospective study of 119 hospitalized pregnant women at the Department of Perinatology, University Clinical Center of the Republic of Srpska in Banja Luka, with gestational age ≥ 27 weeks, singleton pregnancies, and no fetal malformations. CTG tracings were classified as normal, equivocal, or pathological. The BPP was scored (0-10) and categorized as normal, equivocal, or pathological. We correlated test results with UA pH (acidosis < 7.20; pre-acidosis 7.20-7.24; normal ≥ 7.25) and the one-minute AS. We calculated sensitivity, specificity, positive predictive value, negative predictive value, and accuracy, and used appropriate significance tests.

CTG and BPP showed similar predictive performance for detecting acidosis and a low one-minute AS. Both methods demonstrated statistically significant associations with UA pH and AS (p < 0.001). Perinatal mortality was 1.68% and morbidity was 24.37%; fatal outcomes were associated with pathological findings on both tests, acidosis, and a low AS.

CTG and BPP are useful predictors of fetal hypoxia and asphyxia. Integrated use and careful interpretation of both tests can aid in identifying compromised fetuses and guiding timely decisions about the mode and timing of delivery, with the potential to reduce adverse perinatal outcomes.