Barrett J M, Vanhooydonk J E, Boehm F H
Obstet Gynecol. 1981 Apr;57(4):422-5.
A major limitation in the use of the nonstress test (NST) has been the high frequency of nonreactive NSTs in the absence of fetal distress. Exogenous factors causing loss of fetal heart rate reactivity (FHRR) have not been fully evaluated, although it has previously been shown that chronic smokers have an increased incidence of nonreactive NSTs in the absence of fetal distress. A group of chronically smoking high-risk pregnant women at 31 to 44 weeks' gestation was studied to determine if the acute effects of smoking caused the NST to become nonreactive. After a reactive NST was obtained, each patient smoked 1 cigarette and the effects of the fetus were observed. Twenty-six studies were performed on 25 patients. A transient mild elevation of baseline fetal heart rate was noted after smoking in several studies; however, no significant change was found in FHRR, indicating that the acute effects of smoking a single cigarette are not responsible for the increased incidence of nonreactive NSTs in smokers.
无应激试验（NST）使用中的一个主要限制是，在无胎儿窘迫的情况下，无反应性NST的发生率很高。尽管之前已经表明，慢性吸烟者在无胎儿窘迫的情况下，无反应性NST的发生率会增加，但导致胎儿心率反应性（FHRR）丧失的外源性因素尚未得到充分评估。对一组妊娠31至44周的慢性吸烟高危孕妇进行了研究，以确定吸烟的急性效应是否会导致NST变为无反应性。在获得反应性NST后，每位患者吸1支烟，并观察对胎儿的影响。对25名患者进行了26项研究。在几项研究中，吸烟后发现基线胎儿心率有短暂轻度升高；然而，未发现FHRR有显著变化，这表明吸一支烟的急性效应并非导致吸烟者无反应性NST发生率增加的原因。
