Accurate detection of the fetal electrocardiogram (FEKG) during pregnancy may enhance the physician's ability to diagnose fetal distress and congenital cardiac defects. FEKG acquisition is hampered by excessive noise contamination from the maternal EKG (MEKG) and uterine muscular contraction.Methods: A new computerized system was developed to record the FEKG and MEKG signals from multiple abdomen and chest electrodes. Removal of noise sources was performed using a blanking procedure, (which selectively removes MEKG signal) and a signal averaging procedure (which averages adjacent MEKG complex's, and the averaged reference MEKG is subtracted from the abdominal signal). We obtained 25 tracings from 19 women with gestational ages ranging from 17 to 41 weeks. Acceptable traces were defined as those where the fetal QRS could be seen for minimum of 30 seconds with a minimum signal to noise ratio of 2. Results: From the 25 tracings 13 were found to contain acceptable FEKG. Two of the negative results were caused by biological noise with QRS type waveform and frequency of 8.75Hz. The depth of the fetus (5-10 cm) and period of gestation (17-41 weeks) did not appear to be factors in obtaining an adequate FEKG. The maternal QRS complex was blanked out from the FEKG, however part ot the fetal signal was removed making it unusable. The signal averaging procedure using 10-20 maternal QRS's to produce a reference then subtraction still produced occasional false positive fetal QRS signals because the subtraction still produced a small peak at the location of the Maternal QRS. Conclusion: Blanking is not an optimal method for maternal noise removal because it also removes parts of the FEKG complex. Averaging is a viable method except in cases where the peak fetal signals are less than 75 micro Volts.