A review of the nonstress test.

A review of the developmental research and the clinical utilization of the nonstress test (NST) is presented. In contrast to the oxytocin challenge test (OCT), it is more acceptable to patients, takes less time, is easily reproducible and is less expensive. More important, there are no contraindicatioins to the nonstress test as a primary screening device. The salient points in performance of the nonstress test, developed by other investigators as well as the authors in a level III maternity center, are reviewed. Enhanced sensitivity and specificity of this method for fetal evaluation must be pursued. No one criterion for a reactive nonstress test has been universally accepted. Furthermore, which test (NST or OCT) is the first to determine fetal distress remains unresolved. The "standard of care" for bioelectrical evaluation remains pluralistic, and it should be utilized within a system that uses additional modalities of fetal assessment and sound clinical judgment.