The effects of oxytocin on fetal rate variability during labor.

THe effect of oxytocin infusion on fetal heart rate (FHR) variability was studied during 22 normal labors. FHR variability was measured by a microprocessor-based on-line system, which used direct fetal electrocardiogram as a triggering signal for interval analysis. Interval index describing the long term component of FHR variability did not change significantly during the experiment. The differential index describing the short term variability had an almost significant decreasing trend when the dose of oxytocin exceeded six mU/min.