variability
the fetal heart rate normally exhibits fluctuations in baseline heart rate activity that is irregular in amplitude and frequency. the variability is linked to the central nervous system (CNS) reflecting cerebral activity. it is therefore a vital clue in determining the overall fetal condition. detection is most accurate with a scalp electrode, althougt newer external transducers have improved ability to detect variability. absent baseline variability is the most specific finding associated with fetal asphyxia. but has very poor specificity with estimated positive predicitive value ranged from 2.6 to 18.1 percent. variability, whenpresent, is correlated with a good outcome. for structured intermit