Automatic detection of fetal movement by Doppler ultrasound during non-stress testing.

A new external fetal monitor, using a defocused, wide-area ultrasound transducer has been devised in order to obtain a more accurate representation of fetal movement during antepartum non-stress testing. The fetal activity Doppler signal is easily distinguished from the fetal heart Doppler and provides an automatic record of fetal movement which is objective and reproducible. In several clinical tests, this new monitor was found to be more sensitive and reliable than either reports of fetal movement from the mother or from a physician palpating the abdomen. This method of automatic detection of fetal activity can improve the accuracy of the non-stress test by providing an additional objective criteria.