Fetal movement detection: Comparison of the Toitu actograph with ultrasound from 20 weeks gestation

Janet A. DiPietro, Kathleen A. Costigan, Eva K. Pressman

Research output: Contribution to journalReview articlepeer-review


Objective: This study evaluates the validity of Doppler-detected fetal movement by a commercially available monitor and investigates whether characteristics of maternal body habitus and the intrauterine environment affect its performance. Methods: Fetal movement was evaluated in normal pregnancies using both ultrasound visualization and a fetal actocardiograph (Toitu MT320; Tofa Medical Inc., Malvern, PA). Data were collected for 32 min on 34 fetuses stratified by gestational age (20-25 weeks; 28-32 weeks; 35-39 weeks). Fetal and maternal characteristics were recorded. Comparisons between ultrasound-detected trunk and limb movements and actograph records were conducted based both on 10-s time intervals and on detection of individual movements. Results: Time-based comparisons indicated agreement between ultrasound and actograph 94.7% of the time; this association rose to 98% when movements of less than 1 s duration were excluded. Individual movements observed on ultrasound were detected by the actograph 91% of the time, and 97% of the time when brief, isolated movements were excluded. The overall kappa value for agreement was 0.88. The actograph was reliable in detecting periods of quiescence as well as activity. These findings did not vary by gestational age. The number of movements detected by the actograph, but not the single-transducer ultrasound, significantly increased over gestation. Maternal age, parity, weight, height, or body mass index were not consistently associated with actograph validity. Characteristics of the uterine environment, including placenta location, fetal presentation, and amniotic fluid volume also did not affect results. Conclusions: The Toitu actograph accurately detects fetal movement and quiescence from as early as 20 weeks gestation and has utility in both clinical and research settings. Actographs are most useful for providing objective and quantifiable measures of fetal activity level, including number and duration of movements, while visualization through ultrasound is necessary for studies of movement quality, source, or mechanics.

Original languageEnglish (US)
Pages (from-to)237-242
Number of pages6
JournalJournal of Maternal-Fetal and Neonatal Medicine
Issue number6
StatePublished - 1999


  • Actocardiograph
  • Fetal heart rate
  • Fetal monitoring
  • Fetal movement

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Obstetrics and Gynecology


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