(232) Fetal Electroencephalography as a Predictor of Distress in Labor: A Retrospective Analysis of 140 Cases

Objective:
Fetal heart rate (FHR) monitoring is the standard for assessing fetal status during labor, but it is often equivocal and has low positive predictive value (PPV) for fetal distress. Despite its widespread use, rates of neurologic injury from birth have not declined, while cesarean deliveries have increased. Fetal electroencephalography (EEG) has been proposed as a complementary tool to better assess neurologic risk.

Study Design:
We analyzed data from 140 laboring individuals (31 weeks to term) with fetal EEG recorded via a fetal scalp electrode (FSE). Data included FHR tracings, fetal scalp pH, cord gases, and 1-minute Apgar scores. EEG was recorded using a suction-mounted silver chloride electrode. Fetal distress was defined as pH ≤ 7.20 and/or Apgar < 7. Abnormal EEG was defined as reduced amplitude/frequency, absent sleep cycling, or near-isoelectric tracing. We calculated sensitivity, specificity, PPV, and negative predictive value (NPV) of EEG and compared it to Category II/III FHR tracings.

Results:
Among 33 cases of fetal distress, 26 had abnormal EEGs and 7 had normal EEGs. Among 107 without distress, 103 had normal EEGs and 4 had abnormal EEGs (Table 1). EEG showed sensitivity of 79%, specificity of 96%, PPV of 87%, and NPV of 94%. These values were higher than those observed with FHR monitoring and consistent with published data (Table 2).

Conclusion:
Fetal EEG during labor correlates with indicators of distress, including low pH and Apgar scores. Compared to FHR monitoring, EEG demonstrated superior specificity, PPV, and NPV. EEG may serve as a valuable adjunct to FHR monitoring to improve fetal neurologic assessment and perinatal outcomes.