Rotmensch S, Luo J S, Liberati M, Belanger K, Mahoney M J, Hobbins J C
Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, CT 06510-8063.
Am J Obstet Gynecol. 1992 May;166(5):1330-4. doi: 10.1016/0002-9378(92)91599-6.
Our aim was to evaluate the utility of ultrasonographic humeral length measurements for detection of fetuses with Down syndrome in the midtrimester of gestation.
Ultrasonographic biometry data obtained before genetic amniocenteses on 43 fetuses with Down syndrome and 204 randomly chosen normal fetuses were analyzed. Regression equations relating biparietal diameter to humeral length and femoral length were used to calculate ratios of observed-to-expected length and sensitivity and specificity at various cutoff points.
Humeral length in Down syndrome fetuses was significantly shorter than in normal controls (p less than 0.001). A ratio of 0.90 for observed/expected humeral length yielded a sensitivity of 28%, a specificity of 91%, and positive predictive values of 1.23% and 0.41% in populations at risk for Down syndrome of 1 in 250 and 1 in 750, respectively. The equivalent ratio for femoral length yielded a sensitivity of 19%, a specificity of 91%, and positive predictive values of 0.87% and 0.28% for baseline risks of 1 in 250 and 1 in 750, respectively.
The sensitivity of fetal humeral length measurements for Down syndrome detection in our hands was remarkably lower than previously reported. Independence of this parameter from currently used serum screening markers has not been established; therefore implementation in screening programs is not advisable at this point.
我们的目的是评估超声测量肱骨长度在孕中期检测唐氏综合征胎儿中的效用。
分析了43例唐氏综合征胎儿和204例随机选择的正常胎儿在进行遗传羊膜穿刺术前获得的超声生物测量数据。使用双顶径与肱骨长度和股骨长度的回归方程来计算观察到的与预期长度的比率以及在不同临界点的敏感性和特异性。
唐氏综合征胎儿的肱骨长度明显短于正常对照组（p<0.001）。在唐氏综合征风险分别为1/250和1/750的人群中，观察到的/预期的肱骨长度比率为0.90时，敏感性为28%，特异性为91%，阳性预测值分别为1.23%和0.41%。股骨长度的等效比率在基线风险为1/250和1/750时，敏感性分别为19%和特异性为91%，阳性预测值分别为0.87%和0.28%。
在我们的研究中，胎儿肱骨长度测量用于检测唐氏综合征的敏感性显著低于先前报道。该参数与目前使用的血清筛查标志物的独立性尚未确立；因此，目前不宜在筛查项目中实施。
