A Fetal Phonocardiotachometer for Use in Labor

Certain obstetrical problems in labor affecting the unborn baby may result in death of the baby before and after birth or may be responsible for brain damage disorders. Because these problems occur frequently, it is necessary to evaluate fetal well-being as closely as possible in labor. The use of the fetal heart rate as an indication of the fetal condition in labor is discussed and the necessity for constant monitoring of the fetal heart rate is emphasized. The special problems associated with monitoring in labor are noted. A fetal phonocardiotachometer is described which operates with an acoustic signal to noise ratio of +3 db after filtering to monitor heart rate over a range of approximately 70 to 210 beats per minute. It will follow a maximum rate of change of rate within this range of six beats per minute per second. So far over 300 cases were followed with the instrument.