Lauria M R, Zador I E, Bottoms S F
Wayne State University/Hutzel Hospital, Department of Obstetrics and Gynecology, Detroit, Michigan 48201, USA.
Ultrasound Obstet Gynecol. 1995 May;5(5):308-12. doi: 10.1046/j.1469-0705.1995.05050308.x.
Current ultrasound morphometric tables estimate centiles assuming normal distribution and similar variation throughout gestation. Our goal was to develop normative tables for biparietal diameter, femur length and average abdominal diameter using actual centiles. We studied the last complete ultrasound examination from 9510 singleton, live pregnancies without major malformations delivered at our hospital. Actual 5th, 10th, 50th, 90th and 95th centiles were calculated for each week and compared to estimates based on means and standard deviations. With advancing gestational age, variation in average abdominal diameter increased and variation in biparietal diameter and femur length remained stable. The largest difference between an actual and an estimated centile limit was 2 mm for biparietal diameter or femur length and 3 mm for average abdominal diameter. Differences between true and estimated centile limits were less than the intraobserver variation of the ultrasound measurements and therefore clinically unimportant.
当前的超声形态测量表在假设整个孕期呈正态分布且变异相似的情况下估算百分位数。我们的目标是使用实际百分位数制定双顶径、股骨长度和平均腹径的标准表。我们研究了我院分娩的9510例单胎、活产且无重大畸形的妊娠中最后一次完整的超声检查。计算了每周的实际第5、10、50、90和95百分位数，并与基于均值和标准差的估计值进行比较。随着孕周增加，平均腹径的变异增加，而双顶径和股骨长度的变异保持稳定。实际和估计的百分位数界限之间的最大差异，双顶径或股骨长度为2毫米，平均腹径为3毫米。真实和估计的百分位数界限之间的差异小于超声测量的观察者内变异，因此在临床上并不重要。
