Brown R, Patrick J
Am J Obstet Gynecol. 1981 Nov 15;141(6):646-51. doi: 10.1016/s0002-9378(15)33305-6.
Longer observation intervals might increase the positive predictive value of a nonreactive nonstress test (NST). One thousand one hundred and one NSTs were performed on 343 fetuses in 333 high-risk hospitalized patients. Recordings were terminated when five fetal heart rate (FHR) accelerations with movement occurred in any 20-minute period or after 120 minutes. The conclusion drawn was that the positive predictive value for morbidity and mortality of a nonreactive NST was 85.7% if conducted over 120 minutes, and that the negative predictive value for a reactive NST was 98.5%. A reactive NST was predictive of good fetal health regardless of the length of observation time necessary to demonstrate reactivity up to 120 minutes.
更长的观察间隔可能会提高无应激试验（NST）无反应型结果的阳性预测值。对333例高危住院患者的343例胎儿进行了1101次NST。当在任何20分钟时间段内出现5次伴有胎动的胎儿心率（FHR）加速或在120分钟后，记录终止。得出的结论是，如果NST持续120分钟以上，无反应型结果对于发病率和死亡率的阳性预测值为85.7%，而反应型结果的阴性预测值为98.5%。无论显示反应型结果所需的观察时间长短（最长120分钟），反应型NST都可预测胎儿健康状况良好。
