Gupta R, Thomas R D, Sreenivas V, Walter S, Puliyel J M
Department of Pediatrics and Neonatology, St Stephen's Hospital, Tis Hazari, Delhi, India.
Am J Perinatol. 2001 Jun;18(4):217-24. doi: 10.1055/s-2001-15500.
An observational prospective study reported that newborn babies with Down syndrome (DS) had short upper limbs that reach up to their pelvis. The shortening was most marked in the forearm (the middle segment of the upper limb) and this relative shortening resulted in an alteration of the proximal to middle segment length ratio. This study assumes that there is a similar alteration in the ratio of the lower limb. We propose to study the proximal to middle segment ratio in the lower limb in normal fetuses at different gestational ages. Against these norms we propose to study the ratio in fetuses with DS to see at what stage in intrauterine life the altered ratio becomes evident. We also propose to take postnatal measurements of upper and middle segments of both upper and lower limbs of babies born with DS and compare them with normal babies. Fetal femoral and tibial lengths were measured by routine antenatal ultrasound scans at a General hospital with 6000 deliveries a year. All babies delivered were examined for phenotypical evidence of DS. The in utero measurements recorded of babies born with DS were compared with the measurements in normal babies. Postnatal measurements of the arm and forearm, and the thigh and leg of babies with DS were taken soon after birth. These were compared with a control group of 20 consecutive normal babies born over 2 days. There were 3690 readings of 3075 normal fetuses and 8 measurements of 7 Down fetuses. The leg, the upper arm, and arm of newborns with DS were significantly shorter than controls (p<0.01). The upper limb reached up to the pelvis in infants with DS and not up to mid thigh as in normal babies. The forearm was shorter than the arm in infants with DS. This is a reversal of the ratio seen in controls. The ratio of femoral to tibial length remains near constant at 1.1 after 13 weeks' gestation in normal fetuses. It rises from 1.2 to 1.4 from 22 weeks' to 38 weeks' gestation in fetuses with DS. The mean standard deviation score of fetuses with DS was 4.53 compared with norms (SD 1.7, p<0.01). Conclusions of this study are: (1) short upper limbs (reaching only up to the pelvis) is a clinical feature of DS at birth; and (2) after 20 weeks' gestation, the ratio of femoral-tibial length can be a marker of DS in utero.
一项前瞻性观察研究报告称，患有唐氏综合征（DS）的新生儿上肢短小，仅能触及骨盆。这种缩短在前臂（上肢的中间部分）最为明显，这种相对缩短导致了近端与中间段长度比例的改变。本研究假定下肢的该比例也有类似改变。我们提议研究不同孕周正常胎儿下肢的近端与中间段比例。以此为参照标准，我们提议研究患有唐氏综合征胎儿的该比例，以观察在子宫内生活的哪个阶段该改变的比例变得明显。我们还提议对患有唐氏综合征的新生儿的上肢和下肢的上段和中段进行出生后测量，并与正常婴儿进行比较。在一家每年有6000例分娩的综合医院，通过常规产前超声扫描测量胎儿的股骨和胫骨长度。对所有分娩的婴儿进行唐氏综合征的表型证据检查。将患有唐氏综合征的婴儿在子宫内记录的测量值与正常婴儿的测量值进行比较。对患有唐氏综合征的婴儿出生后不久进行手臂和前臂以及大腿和小腿的出生后测量。将这些测量值与连续两天出生的20例正常婴儿的对照组进行比较。对3075例正常胎儿进行了3690次测量，对7例唐氏胎儿进行了8次测量。患有唐氏综合征的新生儿的腿部、上臂和手臂明显短于对照组（p<0.01）。患有唐氏综合征的婴儿上肢仅能触及骨盆，而不像正常婴儿那样能触及大腿中部。患有唐氏综合征的婴儿前臂比上臂短。这与对照组的比例相反。正常胎儿在妊娠13周后股骨与胫骨长度的比例保持在1.1左右恒定。患有唐氏综合征的胎儿在妊娠22周时该比例从1.2上升到38周时的1.4。患有唐氏综合征的胎儿的平均标准差分数与标准值相比为4.53（标准差1.7，p<0.01）。本研究的结论是：（1）上肢短小（仅能触及骨盆）是唐氏综合征出生时的一个临床特征；（2）妊娠20周后，股骨 - 胫骨长度比例可作为子宫内唐氏综合征的一个标志物。
