Hyett J A, Sebire N J, Snijders R J, Nicolaides K H
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital Medical School, London, UK.
Ultrasound Obstet Gynecol. 1996 Feb;7(2):101-3. doi: 10.1046/j.1469-0705.1996.07020101.x.
This study investigates whether first-trimester screening for trisomy 21 by fetal nuchal translucency thickness preferentially identifies those fetuses destined to die in utero and examines the potential impact of such a method of screening on the live birth incidence of trisomy 21. In 70 pregnancies, trisomy 21 was diagnosed at 12 (range 11-14) weeks of gestation and the parents opted for elective termination which was carried out at 14 (12-20) weeks. In all cases, viability was established by ultrasound scan at the time of chorion villus sampling (CVS) and just before termination of pregnancy. Eight (11.4%) fetuses died in the interval between CVS and termination of pregnancy and this rate of lethality was higher than the 6.9% estimated rate for an unselected population of trisomy 21 fetuses. This 4.5% increase may, in part, be attributed to the effects of CVS and may also be due to patient selection on the basis of increased nuchal translucency. The rate of lethality increased with translucency thickness from 5.3% for those with translucency of 1-3 mm to 23.5% for translucency of > 7 mm. In trisomy 21, the rate of intrauterine lethality is associated with nuchal translucency thickness. Nevertheless, a policy of screening by maternal age and fetal nuchal translucency followed by selective termination of affected fetuses would still result in a more than 70% reduction in the live birth incidence of trisomy 21.
本研究调查了通过胎儿颈部半透明厚度进行孕早期21三体综合征筛查是否会优先识别出那些注定会在子宫内死亡的胎儿，并探讨了这种筛查方法对21三体综合征活产发生率的潜在影响。在70例妊娠中，于妊娠12周（范围11 - 14周）诊断出21三体综合征，父母选择了选择性终止妊娠，于14周（12 - 20周）进行。在所有病例中，在绒毛取样（CVS）时以及即将终止妊娠前通过超声扫描确定胎儿存活能力。8例（11.4%）胎儿在CVS与终止妊娠之间的间隔期死亡，这一致死率高于未选择的21三体综合征胎儿群体估计的6.9%的致死率。这4.5%的增加部分可能归因于CVS的影响，也可能是由于基于颈部半透明性增加进行的患者选择。致死率随半透明厚度增加而上升，半透明厚度为1 - 3毫米者的致死率为5.3%，而半透明厚度大于7毫米者的致死率为23.5%。在21三体综合征中，子宫内致死率与颈部半透明厚度相关。然而，采用基于孕妇年龄和胎儿颈部半透明厚度进行筛查，随后对受影响胎儿进行选择性终止妊娠的政策，仍将使21三体综合征的活产发生率降低70%以上。
