评估泰国人群中胎儿股骨长度以检测唐氏综合征。

Evaluation of fetal femur length to detect Down syndrome in a Thai population.

作者信息

Tannirandorn Y, Manotaya S, Uerpairojkit B, Tanawattanacharoen S, Wacharaprechanont T, Charoenvidhya D

机构信息

Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Faculty of Medicine, King Chulalongkorn Memorial Hospital, Chulalongkorn University, Bangkok, Thailand.

出版信息

Int J Gynaecol Obstet. 2001 May;73(2):117-23. doi: 10.1016/s0020-7292(01)00347-2.

DOI:10.1016/s0020-7292(01)00347-2

PMID:11336730

Abstract

OBJECTIVE

To assess the value of femur length shortening for prenatal detection of Down syndrome in a Thai population.

METHOD

A prospective study was performed by experienced perinatologists on 3137 women undergoing second-trimester amniocentesis, between 16 and 24 weeks of gestation, for the indications of advanced maternal age and past history of chromosomal abnormality. Biparietal diameter and femur length measurements were obtained before the procedures. Regression equations relating biparietal diameter to femur length were used to calculate observed femur length/expected femur length ratio in the chromosomally normal and Down syndrome fetuses. Sensitivity, specificity, false-positive rate and likelihood ratio of a positive test result at various observed femur length/expected femur length ratios for detection of Down syndrome were calculated. A receiver-operator characteristic curve was used to determine threshold screening ratio.

RESULTS

There were 3084 chromosomally normal pregnancies, 26 fetuses with Down syndrome (1:118), and 27 other chromosomal abnormalities. The relationship between femur length and biparietal diameter (BPD) was: expected femur length=-7.631+0.814 BPD, R(2)=0.78, P<0.001). Femur length in Down syndrome fetuses was significantly shorter than in normal fetuses (P<0.001). A ratio of 0.91 for observed femur length/expected femur length yielded a sensitivity of 42.3%, specificity of 86.2%, false positive rate of 13.8% and likelihood ratio of a positive test result of 3.07 (95% CI 1.94-4.84) for detection of Down syndrome.

CONCLUSIONS

In this study, femur length shortening in the second trimester appears to be a useful screening parameter for fetal Down syndrome in a Thai population.

摘要

目的

评估股骨长度缩短在泰国人群中对唐氏综合征产前检测的价值。

方法

由经验丰富的围产医学专家对3137名在妊娠16至24周因高龄产妇及既往染色体异常病史而接受孕中期羊膜腔穿刺术的孕妇进行前瞻性研究。在操作前测量双顶径和股骨长度。使用双顶径与股骨长度的回归方程来计算染色体正常和唐氏综合征胎儿的观察股骨长度/预期股骨长度比值。计算了不同观察股骨长度/预期股骨长度比值下检测唐氏综合征的阳性检测结果的敏感性、特异性、假阳性率和似然比。使用受试者操作特征曲线来确定阈值筛查比值。

结果

有3084例染色体正常妊娠、26例唐氏综合征胎儿（1:118）和27例其他染色体异常。股骨长度与双顶径（BPD）的关系为：预期股骨长度 = -7.631 + 0.814BPD，R(2)=0.78，P<0.001）。唐氏综合征胎儿的股骨长度明显短于正常胎儿（P<0.001）。观察股骨长度/预期股骨长度比值为0.91时，检测唐氏综合征的敏感性为42.3%，特异性为86.2%，假阳性率为13.8%，阳性检测结果的似然比为3.07（95%CI 1.94 - 4.84）。