Tannirandorn Yuen, Manotaya Saknan, Uerpairojkit Boonchai, Tanawattanacharoen Somchai, Wacharaprechanont Teera, Charoenvidhya Dhiraphongs
Department of Obstetrics and Gynecology, Faculty of Medicine, King Chulalongkorn Memorial Hospital, Chulalongkorn University, Bangkok, Thailand.
J Obstet Gynaecol Res. 2002 Apr;28(2):89-94. doi: 10.1046/j.1341-8076.2002.00013.x.
To assess the value of humerus length shortening for prenatal detection of Down syndrome in a Thai population.
A prospective study was performed on 3053 women undergoing second-trimester amniocentesis, between 16 and 24 weeks gestation, for the indications of advanced maternal age and a past history of chromosomal abnormality. Biparietal diameter (BPD) and humerus length measurements were obtained before the procedures. Regression equations relating BPD to humerus length were used to calculate observed humerus length/expected humerus length ratio in chromosomally normal and Down syndrome fetuses. Sensitivity, specificity, false-positive rate and likelihood ratio of a positive test result at various observed humerus length/expected humerus length ratios for detection of Down syndrome were calculated. A receiver-operator characteristic curve was used to determine the threshold screening ratio.
There were 3003 chromosomally normal pregnancies and 24 fetuses with Down syndrome. The relationship between humerus length and BPD was: expected humerus length = 0.7403BPD - 5.1057, R2= 0.77, P < 0.001. Humerus length in Down syndrome fetuses was significantly shorter than in normal fetuses (P < 0.001). A ratio of 0.91 for observed humerus length/expected humerus length yielded a sensitivity of 41.7%, specificity of 88.3%, a false-positive rate of 11.7% and likelihood ratio of a positive test result of 3.63 (95% confidence interval 2.24-5.88) for detection of Down syndrome.
Humerus length shortening in the second trimester appears to be a useful adjunctive screening parameter for fetal Down syndrome in a Thai population.
评估肱骨长度缩短在泰国人群中对唐氏综合征产前检测的价值。
对3053名妊娠16至24周因高龄产妇及既往有染色体异常病史而接受孕中期羊膜腔穿刺术的妇女进行了一项前瞻性研究。在手术前测量双顶径（BPD）和肱骨长度。使用将BPD与肱骨长度相关的回归方程来计算染色体正常和唐氏综合征胎儿的观察到的肱骨长度/预期肱骨长度比值。计算了在各种观察到的肱骨长度/预期肱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。使用受试者工作特征曲线来确定阈值筛查比值。
有3003例染色体正常的妊娠和24例唐氏综合征胎儿。肱骨长度与BPD之间的关系为：预期肱骨长度 = 0.7403BPD - 5.1057，R2 = 0.77，P < 0.001。唐氏综合征胎儿的肱骨长度明显短于正常胎儿（P < 0.001）。观察到的肱骨长度/预期肱骨长度比值为0.91时，检测唐氏综合征的敏感性为41.7%，特异性为88.3%，假阳性率为11.7%，阳性检测结果的似然比为3.63（95%置信区间2.24 - 5.88）。
孕中期肱骨长度缩短似乎是泰国人群中胎儿唐氏综合征有用的辅助筛查参数。
