Study of two definitive methods of fetoscopic ausculation

Significant perinatal research in the past 10 years with fetal electrocardiography, biophysical and biochemical assays has mad remarkable progress in attempting to define criteria for fetal distress. Correlations made between the immediate and subsequent (up to 5 years of age) normal and abnormal physical, physiological and neurological development of the child are noteworthy. Caldeyro-Barcia has described fetal heart rate changes and delineated two indicative criteria of fetal distress. He identified 4 variations and defined a base line up which these variations are superimposed. 1. Rapid fluctuations, 2. Spikes, 3. Transcient ascents, 4. Type I and Type II dips with their differentiating amplitudes and lag times make up these variations. The two indicative criteria of fetal distress are: persistent rise in the basal fetal heart rate and a great number of type II dips. Type II dips consist of a fall in rate which starts at or follows the pad of uterine contraction reaching a minimum value 30 to 50 seconds later, and recovers to initial values in about the same length of time as the fall. This type II dip pattern, when found in large numbers, with a total amplitude greater than 600 beats per minute (by electronic monitoring) is an abnormal sign. When present, as described, the newborn is depressed at birth and has an Apgar score of 6 or less. Method I follows the correct method"" described for clinical auscultation and recording of fetal heart rates by Caldeyro-Barcia. Method II is an adaptation of this counting and recording sequence which meets the minimum requirements of the American College of Obstetricians and Gjmecolo-gists for listening and recording fetal heart rates during labor. Twenty mothers were followed during their labor experiences, Method I was used at hourly intervals and method II at half hour intervals on each mother. An individual base line was established for each counting sequence using the average count sequence taken while the uterus was at rest. In this group of patients, no abnormal fetal heart rate patterns were found that met the criteria outlined by Caldeyro-Barcia. Results show that irregularities in the fetal heart rate could be found by the nurse, in clinical practice, using definitive methods of auscultation and recording. The nurse could perform nursing procedures during the first stage of labor along with the auscultation and recording sequences on the mother she was following. All mothers in this study tolerated the 6 minute 40 second auscultation sequences during labor. Prolonged listening time for one patient which decreased the time available for other patients, sustained concentration for listening and recording, time necessary for analyzing data, fatigue during lengthy labors, and compromised data, are limitations found during this study which would prevent general application of the procedure. It would be feasible to utilize this ""correct method"" on mothers or infants placed in a high risk category. Delineation of patterns in fetal heart rates would provide a more scientific basis for obstetrical management.""