(1117) Noninvasive Fetal EEG Validation Using Auditory Event-Related Potentials in Third-Trimester Pregnancies

Objective:
There are no clinically available tools for assessing fetal brain function in utero. Functional MRI and magnetoencephalography can detect fetal brain activity but require costly, non-portable equipment and magnetically shielded rooms. We developed the first system capable of noninvasively extracting fetal electroencephalography (EEG) signals from the maternal abdomen. EEG is portable, low-cost, and widely available, but until now, fetal EEG could not be reliably measured noninvasively.

Study Design:
We collected abdominal EEG during non-stress tests (NSTs) in third-trimester pregnancies. Recordings lasted 20 minutes with randomly timed 85 dB auditory stimuli to elicit fetal neurologic responses. Our proprietary algorithm filtered non-fetal signals and extracted fetal EEG responses. We analyzed event-related potentials (ERPs) by examining spatial distribution, latency, and associations with gestational age and birth outcomes. Statistical significance was assessed using a nonparametric permutation test that controls for multiple comparisons.

Results:
Fetal EEG was collected from 97 singleton pregnancies (29–39 weeks gestation). Maternal BMI ranged from 15.8–36 kg/m², and maternal age from 26–47 years. All subjects had reactive NSTs. Fetal presentations included cephalic (78), breech (14), and transverse (5). ERPs were successfully extracted from all 97 fetuses. ERP heatmaps were generated for each subject, and a grand average waveform confirmed a consistent response (Figure 1). A statistically significant ERP signal was observed during the 150–800 ms post-stimulus interval (Figure 2).

Conclusion:
This is the first large-scale demonstration of in utero fetal brain responses to auditory stimuli using noninvasive EEG. These findings establish the feasibility of real-time fetal brain monitoring in clinical settings.