Comparison of cardiotocograms prepared by abdominal electrocardiography and by ultrasound cardiography.

Cardiotocograms were prepared in 127 cases on 120 pregnant women, first by abdominal electrocardiography, and immediately afterwards by ultrasound cardiography. A study was made to ascertain which method yielded recordings of higher quality, and which factors influenced the quality of the cardiotocogram. It was found that the proportion of good-quality recordings was higher with ultrasound cardiography than with abdominal electrocardiography. The higher information content of the latter technique allows a more accurate assessment of the cardiotocograms. The recording quality is affected by numerous factors, the most important of which are adiposity and the duration of pregnancy. The use of abdominal electrocardiography is preferred in case of a thick abdominal wall, whereas the ultrasound technique is recommended between the 28th and 36th weeks of pregnancy.