Characterization of fetal body movement recorded by the Hewlett-Packard M-1350-A fetal monitor

OBJECTIVE: The purpose of this study was to evaluate the ability of a commercially available monitor, the Hewlett-Packard M-1350-A fetal monitor, to record and discriminate between various fetal body movements. STUDY DESIGN: Twenty-four patients between 29 and 42 weeks' gestation were monitored over a 20 to 30 minute period simultaneously by the Hewlett-Packard instrument and ultrasonography. RESULTS: All 593 single or clustered fetal movements recorded by the monitor were seen ultrasonographically as being extremity movements that were either isolated or combined with trunk motion. Discriminating between these two types of movements was not possible on the basis of the duration of recorded movements. All adequate fetal heart rate accelerations were attributed to combined trunk and extremity movements. Detection of fetal hiccups was less exact, and recording of fetal hand, mouth, breathing, and rapid eye movements was beyond the sensitivity of the monitor. Signal artifacts were attributable to either motion of the maternal abdomen or Doppler transducer and became less of a problem with experience. CONCLUSION: Fetal extremity movements were recorded with accuracy by this new fetal monitor.