Also found in: Dictionary, Thesaurus, Legal, Financial, Encyclopedia, Wikipedia.
nonstress test(NST) [non-stres´]
evaluation of fetal well being during the intrauterine period. Observations of fetal heart rate response to fetal movements are made: a reactive pattern of more than 15 beats per minute above the baseline heart rate twice in 10 minutes is indicative of well being; a nonreactive pattern may indicate asphyxia, maternal medication, fetal anomalies, or a prolonged rest state. See also fetal monitoring.
a test to evaluate fetal well-being by evaluating fetal heart rate response to fetal movement; a reactive nonstress test is fetal heart rate acceleration in response to fetal movement.
An ultrasound examination of a fetus that measures fetal well-being by correlating fetal movement with changes in fetal heartbeat.