A system for monitoring a brain wave response of a fetus in utero, comprises removably connecting an auditory transducer, including at least one biosensor electrode, producing pulsed auditory sounds to a mother's abdomen to detect brain wave activity in a fetus. The transducer is pulsed with one of rectangular waves and tone pips of a selected frequency to emit pulsed audible sounds at predetermined times. The at least one biosensor electrode, including connected amplifier, detects brain stem auditory responses (BAER) of the fetus. For each pulsed audible sound a series of voltage oscillations corresponding to BAER of the fetus are time-locked to the corresponding audible sound. BAER analog output is converted to BAER digital data. A computer-based QEEG (Quantitative EEG) system improves a signal to noise ratio of the BAER digital data using an adaptive optimum filtering algorithm and analyzes the BAER digital data relative to a reference database.