A comparison of the three methods for external fetal cardiography

Phonocardiography, abdominal electrocardiography and ultrasound cardiography are the three methods for external fetal cardiography. In the present study the methods have been compared regarding the quality of the graphs. The patients (163) were between the 34th and the 40th week of gestation. Graphs with less than 15 per cent failure or artifacts were found in 23.4 per cent for phonocardiography, 55.2 per cent for abdominal electrocardiography and 85.9 per cent for ultrasound cardiography. It could be shown that the number of successful abdominal electrocardiograms was higher with advancing gestational age. The quality of the phonocardiograms was influenced adversely by an anterior placenta. No obvious influence of a thick abdominal wall on external cardiography could be demonstrated.