Ambulatory tocodynamometry data interpretation: evaluating variability and reliability.
The inter- and intra-observer variabilities of interpretation of uterine activity monitoring data were determined from the interpretations of 20 ambulatory tocodynamometry records by nine physicians and nurses. The presence of contractions lasting less than 40 seconds or presenting at a frequency of fewer than four per hour was associated with significantly reduced accuracy of interpretation. The reliability was 70% with one observer, 82% with two observers, and 88% with three observers. Higher variability and lower reliability values were obtained for interpretation of low-amplitude, high-frequency contractions. Understanding the limitation of uterine activity data interpretation should help in the clinical management of monitored patients.