The fetal heart rate is a key element to monitor a fetus's health status. Fetal heart monitoring using phonocardiography has been proposed because the commonly used Doppler ultrasonic monitoring has some drawbacks. To extract the fetal heart rate from the feeble phonocardiographic signal mixed with noise and interference, an adaptive real-time method is proposed in this paper. Adaptive heartbeat patterns are used in the method to match the recorded heart sound signal and extract the fetal heart rate effectively. The method has been realized on a low-power DSP in real time and its reliability has been verified preliminarily.