A wireless radiotelemetry system for monitoring fetal heart rate and intrauterine pressure during labor and delivery.

A wireless radio telemetry system for the continuous monitoring of fetal heart rate and intrauterine pressure during labor has been designed, constructed, and clinically tested. The system is based upon a miniature or microminiature battery powered two-channel radio transmitter which can be located near or within the vagina respectively. The range of transmission is 10 to 20 m. A noise reducing cardiotachometer is incorporated in the system to reduce artifact by imposing amplitude, duration, and interval criteria to recognize fetal beats. A clinical evaluation of the monitor on 10 patients for an average time of 215 min has shown it to be equivalent to conventional wire monitoring techniques.