title: Observations in perinatal heart rate monitoring. I. A quantitative method of describing baseline variability of the fetal heart rate.
abstract: Simultaneous magnetic tape recordings of fetal scalp ECG, maternal ECG and uterine contractions were obtained from 23 patients in active labor. Computer-derived distributions of beat-to-beat changes were used to develop a simple numerical and graphical description of the long and short-term variability patterns. The visually observed variability may be described by the R-R interval change (beat-to-beat change), which is greater than 90% of the total number of beat-to-beat changes. Thus, the 90th percentile of R-R interval changes quantitatively describes the baseline variability. The variability may be classified as fixed, minimal, moderate or marked, based on this simple calculation. Graphs of cumulative percentage of R-R interval changes provide additional visual information. The effects of meperidine HCl on the observed variability were easily detected and visualized by these methods.
mesh_terms: D004562:Electrocardiography; D005260:Female; D005318:Fetal Heart / Q000503:physiopathology*; D005323:Fetal Monitoring; D006339:Heart Rate; D006801:Humans; D011247:Pregnancy; D014590:Uterine Contraction