Comprehensive fetal monitoring by microcomputer--a clinical approach

The relationship between uterine contractions, fetal movements and fetal heart rate patterns in the active phase of labor

The relationship between fetal movements, fetal heart rate and uterine contractions was studied with a computerized system in 18 parturients during the active phase of labor. 80% of FHR accelerations and 39% of uterine contractions were associated with fetal trunk movements. The probability of association was greater in longer movements and larger accelerations. 98% of fetal movements which lasted 10-15 s, 98% of accelerations with an amplitude of 25-30 bpm and 96.4% of accelerations with a duration of 40-50 s were associated with fetal trunk movements.

Diminished respiratory sinus arrhythmia in asphyxiated term infants

Spectral analysis techniques were used to quantitate the association between respiration and heart rate variability in eight healthy and eight asphyxiated infants born at term gestation. Respiratory sinus arrhythmia was demonstrated in all healthy infants. This arrhythmia was significantly diminished in asphyxiated newborn infants. We conclude that newborn infants with low Apgar scores have a reduced respiratory sinus arrhythmia and that this reduction could account for the loss of short-term heart rate variability commonly associated with asphyxia.

Human fetal breathing: associated changes in heart rate and beat-to-beat variability

A computerized quantification of fetal heart rate and beat-to-beat variability was performed during and between fetal breathing episodes. Sixteen healthy pregnant women at term participated in the study. The results indicate that fetal breathing is associated with a significant increase in beat-to-beat variability (from 4.48 +/- 1.66 between breathing episodes to 5.80 +/- 2.04 during breathing episodes, p less than 0.01) and a small but significant decrease in fetal heart rate (from 142.7 +/- 8.6 bpm between breathing episodes to 140.4 +/- 8.6 bpm during breathing episodes, p less than 0.05).