孕早期颈项透明层超声筛查在高龄孕妇产前诊断胎儿染色体异常中的应用

Application of ultrasound screening in early pregnancy in prenatal diagnosis of fetal chromosome abnormalities in elderly pregnant women

目的探究孕早期颈项透明层(NT)超声筛查在高龄孕妇产前诊断胎儿染色体异常中的应用价值。方法选择2020年5月至2021年5月于闵行区中心医院接受产前检查的1000例高龄孕妇为研究对象,均对其进行NT筛查及无创DNA检测,按照NT厚度区分为NT增厚组(≥2.5 mm)和NT正常组(<2.5 mm),对比2组孕妇无创DNA染色体核型异常检出率,分析NT增厚与胎儿染色体异常发生率的相关性等,应用Logistic回归分析探究NT增厚对胎儿染色体异常的预测价值。结果研究纳入的1000例孕妇中有50例NT≥2.5 mm,发生率5.00%,50例NT增厚孕妇中经无创DNA检测显示染色体异常6例,异常率12.00%,950例NT正常孕妇中无创DNA检测仅1例出现染色体异常,异常率0.11%,2组间比较差异有统计学意义(P<0.05)。核型分析显示7例染色体异常分别为21三体3例,染色体数目异常2例,18三体2例。染色体异常率分析显示:≥35岁孕妇胎儿染色体异常检出率高于30~34岁孕妇,胎儿女性胎儿染色体异常检出率高于男性胎儿,NT厚度≥5.5 mm胎儿染色体异常检出率高于2.5~<3.5 mm以及3.5~<4.5 mm胎儿(P<0.05)。趋势卡方分析:NT厚度与胎儿染色体异常率呈正相关(P<0.05)。NT增厚对胎儿染色体异常诊断曲线下面积(AUC)值(95%CI)为0.631(0.545,0.718),P=0.004。Logistic回归分析显示NT增厚是胎儿染色体异常独立危险因素(P<0.05)。结论对高龄孕妇开展早期超声NT检测可以作为胎儿染色体无创DNA检测的重要筛查指标,NT增厚胎儿发生染色体异常的风险明显增加。

Objective To explore the application value of nuchal translucency(NT)ultrasound screening in the prenatal diagnosis of fetal chromosomal abnormalities in advanced pregnant women.Methods Choose 1000 who received a prenatal diagnosis in our hospital from May 2020 to May 2021 cases of elderly pregnant women were the subjects of the study.NT screening and non-invasive DNA testing were carried out.The subjects were divided into NT thickened group(≥2.5 mm,50 cases)and NT normal group(<2.5 mm,50 cases)according to NT thickness.(950 cases),compared the detection rates of noninvasive DNA chromosomal abnormalities in the two groups of parturient,compared the differences in the detection rates of fetal chromosomal abnormalities in different pregnant women′s delivery age,fetal sex,and NT thickness,and analyzed the correlation between NT thickening and the incidence of fetal chromosomal abnormalities.Logistic regression analysis was used to explore the predictive value of NT thickening on fetal chromosomal abnormalities.Results Among the 1000 cases of parturient included in the study,50 cases had NT≥2.5 mm,an incidence rate of 5.00%,and 50 cases of NT increased Non-invasive DNA testing in thick parturient women showed 6 cases of chromosomal abnormalities,with an abnormality rate of 12.00%.Among 950 cases of NT normal parturient,non-invasive DNA testing showed chromosomal abnormalities in only 1 case,with an abnormality rate of 0.11%.There was a significant difference between the two groups(P<0.05).Karyotype analysis showed that the 7 cases of chromosomal abnormalities were 3 cases of trisomy 21,2 cases of abnormal chromosome number(28.57%),and 2 cases of trisomy 18.The analysis of chromosome abnormality rate showed that the detection rate of fetal chromosome abnormality in 35 years pregnant women was higher than that of 30~34 years,the detection rate of female fetuses was higher than that of male fetuses,and the detection rate of NT thickness of 5.5 mm was higher than that of 2.5~<3.5 mm and 3.5~<4.5 mm(P<0.05).Trend chi-square correlation analysis showed that NT thickness was significantly positively correlated with the incidence of fetal chromosomal abnormalities(P<0.05).The AUC value (95%CI) for diagnosing fetal chromosomal abnormalities with NT thickening is 0.631 (0.545, 0.718), P=0.004. Logistic regression analysis showed that NT thickening was an independent risk factor for fetal chromosomal abnormalities (P<0.05). Conclusion Early ultrasonographic NT detection can be used as an important screening index for fetal chromosomal non-invasive DNA detection for older parturients, and the risk of chromosomal abnormalities in fetuses with thickened NT is significantly increased.