Castillo R A, Devoe L D, Arthur M, Searle N, Metheny W P, Ruedrich D A
Department of Obstetrics and Gynecology, Medical College of Georgia, Augusta 30912-3710.
Am J Obstet Gynecol. 1989 Jan;160(1):172-5. doi: 10.1016/0002-9378(89)90113-0.
The application of the nonstress test between 24 and 32 weeks' gestation has been limited by high rates of "false" nonreactivity in normal fetuses, by use of term criteria, and the lack of age-appropriate interpretative standards. To establish such standards, we studied 30 normal fetuses undergoing 90-minute fetal heart rate recordings at 2-week intervals from 24 to 32 weeks' gestational age. Using a specially programmed computer we quantified (1) baseline fetal heart rate, (2) incidence of 10- and 15-beat accelerations, and (3) incidence of fetal heart rate decelerations. With a criterion of three 15-beat accelerations per 30 minutes 91% of tests were reactive within 90 minutes. A criterion of three 10-beat accelerations per 30 minutes was associated with 100% reactivity within 60 minutes. Suitable interpretative criteria may be established for nonstress tests before 32 weeks' gestation by extending the testing time or by decreasing the minimum amplitude required of fetal heart rate accelerations.
孕24至32周期间无应激试验的应用受到限制，原因包括正常胎儿中“假”无反应性发生率较高、采用足月标准以及缺乏适合该孕周的解读标准。为了建立此类标准，我们研究了30例正常胎儿，在孕24至32周期间每隔2周进行一次90分钟的胎儿心率记录。使用专门编程的计算机，我们对以下指标进行了量化：（1）胎儿心率基线；（2）10次和15次心跳加速的发生率；（3）胎儿心率减速的发生率。以每30分钟出现三次15次心跳加速为标准，91%的试验在90分钟内呈反应型。以每30分钟出现三次10次心跳加速为标准，60分钟内的反应型率为100%。通过延长检测时间或降低胎儿心率加速所需的最小幅度，可以为孕32周前的无应激试验建立合适的解读标准。
