Abstract: Method and apparatus for long-term, non-invasive measuring of fetal heart rate. The method utilizes the characteristic curves of first and second heart sound received by the preferred electroacoustical converter. The identification and distinction of first and second sounds, furthermore their time relation used for heartbeat identification highly increase the reliability of fetal heart rate determination. The distinction of first and second sound is based on the differences in frequency spectrums measured in a relatively short time window and by the estimation of the power peaks measured on two test frequencies chosen on the two ends of the frequency range of fetal heart sound. The method is implemented in an integrated apparatus to achieve low power consumption for battery-operated long-term measurements. Digital filtering and selective power estimation is applied for continuous computation of power time function on the two test frequencies.

Abstract: A process and apparatus is disclosed for effective home monitoring of uterine contractions of a pregnant woman, in order to provide early warning signs of possible premature birth. Using a transducer of known type, uterine contractions are monitored continuously over a period of time. An electrical signal is generated, which is digitized for processing with simple IC chips. Importantly, only those contractions whose intensity exceeds a threshold value for a duration exceeding a threshold period are stored for future processing and analysis. Analysis of these over-threshold values provides a valuable basis on which to judge the likelihood of premature birth. Limiting the analysis only to such over-threshold values enables the system and equipment to be of a highly simplified, economical construction, suitable for widespread home use yet capable of monitoring over an extended duration.