Borrell A, Farré M T, Echevarría M, Martinez J M, Costa D, Fortuny A
Prenatal Diagnosis Unit, Department of Obstetrics and Gynecology, Hospital Clinic, IDIBAPS (Institut d'Investigacions Biomèdiques August Pi i Sunyer), University of Barcelona Medical School, Barcelona, Catalonia, Spain.
Ultrasound Obstet Gynecol. 2000 Aug;16(2):146-8. doi: 10.1046/j.1469-0705.2000.00200.x.
To assess the natural evolution of nuchal thickness in trisomy 18 fetuses.
Serial measurements of nuchal thickness were performed over a 1- to 5-week period in 17 fetuses with trisomy 18, from the 10th to the 20th week of pregnancy. To avoid a confounding effect due to gestational age, nuchal thickness was also expressed in standard deviations (SD) for the corresponding gestational week. In addition, the changes were assessed in terms of the presence of clinically positive thickening, considered as such when its measurement was above 2.5 SD for the corresponding gestational week.
On the initial nuchal thickness measurement, sensitivity for trisomy 18 decreased from 66% on assessment at 10-13 weeks of gestation to 38% at 14-16 weeks. In serial determinations, a mean increase of 1.3 mm [95% confidence interval (CI), 0.1-2.5] was observed for a mean period of 21 days. When corrected for gestational age, the mean increase of 0.2 SD (95% CI, -1.2 to -1.6) was found to be non-significant. No clinically relevant changes were recorded on re-examination, with nuchal thickening remaining stable in 76% of cases.
Nuchal thickening at re-examination was observed in a similar proportion of trisomy 18 fetuses as when initially observed.
评估18三体胎儿颈部厚度的自然演变情况。
对17例18三体胎儿在妊娠10至20周期间进行了为期1至5周的颈部厚度连续测量。为避免胎龄造成的混杂效应，颈部厚度也以相应孕周的标准差（SD）表示。此外，根据临床阳性增厚情况评估变化，当测量值高于相应孕周的2.5 SD时视为临床阳性增厚。
在最初的颈部厚度测量中，18三体的检出敏感度从妊娠10至13周时评估的66%降至14至16周时的38%。在连续测定中，平均21天内观察到平均增加1.3 mm[95%置信区间（CI），0.1 - 2.5]。校正胎龄后，平均增加0.2 SD（95% CI， - 1.2至 - 1.6）无统计学意义。复查时未记录到临床相关变化，76%的病例颈部增厚保持稳定。
复查时观察到颈部增厚的18三体胎儿比例与最初观察时相似。
