Kopta M M, Tomich P G, Crane J P
Obstet Gynecol. 1981 May;57(5):657-60.
The present study examines the relative accuracy of 2 ultrasonic methods of predicting the estimated date of confinement (EDC). The first technique, mean projected gestational age (MPGA), utilizes 2 fetal biparietal diameter (BPD) readings between 19 and 30 weeks' gestation with at least a 3-week interval between examinations. The 2 values are fitted to the mean of the standard curve as closely as possible and an EDC is predicted. The second method, growth adjusted sonographic age (GASA), is based on 1 BPD measurement in the second trimester and another in the third. The first is plotted on the mean and then readjusted depending on the percentile into which the second falls (below 25, 25 to 75, above 75). The EDC was blindly predicted in 120 patients, 60 by the MPGA method and 60 by the GASA technique. These were compared with 60 controls whose EDCs were predicted on the basis of excellent clinical dates. The interval between the predicted EDC and the actual delivery date was calculated for each patient and the results were compared. There was no statistical difference between the 2 techniques.
本研究考察了两种超声方法预测预产期（EDC）的相对准确性。第一种技术是平均预计胎龄（MPGA），它利用妊娠19至30周之间的两次胎儿双顶径（BPD）读数，两次检查之间至少间隔3周。将这两个值尽可能紧密地拟合到标准曲线的平均值上，并预测预产期。第二种方法是生长调整超声孕周（GASA），它基于孕中期的一次BPD测量和孕晚期的另一次测量。首先将第一次测量值绘制在平均值上，然后根据第二次测量值所处的百分位数（低于25、25至75、高于75）进行重新调整。对120例患者进行了盲法预产期预测，其中60例采用MPGA方法，60例采用GASA技术。将这些结果与60例基于精确临床日期预测预产期的对照组进行比较。计算每位患者预测预产期与实际分娩日期之间的间隔，并比较结果。两种技术之间没有统计学差异。
