Longo D, DeFigueiredo D, Cicero S, Sacchini C, Nicolaides K H
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital Medical School, London, UK.
Ultrasound Obstet Gynecol. 2004 Feb;23(2):143-7. doi: 10.1002/uog.970.
To determine the value of measuring fetal femur and humerus length at 11-14 weeks of gestation in screening for chromosomal defects.
Femur and humerus lengths were measured using transabdominal ultrasound in 1018 fetuses immediately before chorionic villus sampling for karyotyping at 11-14 weeks of gestation. In the group of chromosomally normal fetuses, regression analysis was used to determine the association between long bone length and crown-rump length (CRL). Femur and humerus lengths in fetuses with trisomy 21 were compared with those of normal fetuses.
The median gestation was 12 (range, 11-14) weeks. The karyotype was normal in 920 fetuses and abnormal in 98, including 65 cases of trisomy 21. In the chromosomally normal group the fetal femur and humerus lengths increased significantly with CRL (femur length = - 6.330 + 0.215 x CRL in mm, r = 0.874, P < 0.0001; humerus length = - 6.240 + 0.220 x CRL in mm, r = 0.871, P < 0.0001). In the Bland-Altman plot the mean difference between paired measurements of femur length was 0.21 mm (95% limits of agreement - 0.52 to 0.48 mm) and of humerus length was 0.23 mm (95% limits of agreement - 0.57 to 0.55 mm). In the trisomy 21 fetuses the median femur and humerus lengths were significantly below the appropriate normal mean for CRL by 0.4 and 0.3 mm, respectively (P = 0.002), but they were below the respective 5th centile of the normal range in only six (9.2%) and three (4.6%) of the cases, respectively.
At 11-14 weeks of gestation the femur and humerus lengths in trisomy 21 fetuses are significantly reduced but the degree of deviation from normal is too small for these measurements to be useful in screening for trisomy 21.
确定在孕11至14周时测量胎儿股骨和肱骨长度在筛查染色体缺陷中的价值。
在1018例胎儿妊娠11至14周进行绒毛取样做染色体核型分析前，经腹超声测量其股骨和肱骨长度。在染色体正常胎儿组，采用回归分析确定长骨长度与顶臀长（CRL）之间的关联。比较21三体胎儿与正常胎儿的股骨和肱骨长度。
中位妊娠周数为12周（范围11至14周）。920例胎儿染色体核型正常，98例异常，其中21三体65例。在染色体正常组，胎儿股骨和肱骨长度随CRL显著增加（股骨长度=-6.330+0.215×CRL，单位为mm，r=0.874，P<0.0001；肱骨长度=-6.240+0.220×CRL，单位为mm，r=0.871，P<0.0001）。在Bland-Altman图中，股骨长度配对测量的平均差异为0.21mm（95%一致性界限为-0.52至0.48mm），肱骨长度配对测量的平均差异为0.23mm（95%一致性界限为-0.57至0.55mm）。在21三体胎儿中，股骨和肱骨长度中位数分别比相应的CRL正常均值显著低0.4mm和0.3mm（P=0.002），但分别仅在6例（9.2%）和3例（4.6%）中低于正常范围的第5百分位数。
在孕11至14周时，21三体胎儿的股骨和肱骨长度显著缩短，但偏离正常的程度过小，这些测量值对21三体筛查无用。
