探讨早孕期颈项透明层(NT)增厚胎儿染色体异常的发生情况。

选择2016年1月至2019年1月，于广州市妇女儿童医疗中心进行早孕期胎儿NT检查时，发现NT增厚(NT值≥3.0 mm)的1 261例胎儿为研究对象。回顾性分析其临床病例资料。根据胎儿超声诊断结果，将其分为单纯组(n＝1 017，单纯NT增厚胎儿)和合并组(n＝244，NT增厚合并其他结构畸形胎儿)。其中，1 164例胎儿接受介入性产前诊断，以明确胎儿染色体病发生情况，按照其分属的单纯组与合并组，将其分别纳入单纯亚组(n＝965)与合并亚组(n＝199)。对单纯亚组及合并亚组胎儿染色体病发生率，以及这2个亚组胎儿不同NT值范围的染色体病发生率，采用χ²检验进行统计学比较。本研究遵循的程序符合2013年修订的《世界医学协会赫尔辛基宣言》。

①合并组244例胎儿中，合并的其他结构畸形前3位依次为：囊性淋巴管瘤45例(18.4%)、心脏发育畸形44例(18.0%)及脐膨出23例(9.4%)。②接受介入性产前诊断的合并亚组胎儿染色体病发生率为52.8%(105/199)，显著高于单纯亚组的16.9%(163/965)，并且差异有统计学意义(χ²＝123.900，P<0.001)。③接受介入性产前诊断的合并亚组胎儿，NT值范围分别为3.0～3.9 mm、4.0～4.9 mm、5.0～5.9 mm、≥6.0 mm的染色体病发生率分别为34.8%、60.9%、56.3%、67.3%，均分别高于单纯亚组胎儿的10.8%、20.9%、31.4%、42.9%，并且差异均有统计学意义(χ²＝31.400、P<0.001, χ²＝29.453、P<0.001，χ²＝5.676、P＝0.028，χ²＝6.854、P＝0.014)。

早孕期NT增厚合并其他结构畸形胎儿，或者NT值≥6.0 mm胎儿，其发生染色体病的风险均较大。早孕期发现胎儿NT增厚时，应进行胎儿心脏结构筛查。

To explore occurrence of chromosomal abnormality in fetuses with increased nuchal translucency (NT) thickness at first trimester.

From January 2016 to January 2019, a total of 1 261 fetuses with increased NT(≥3.0 mm) thickness at first trimester were selected as research subjects. Their case data were analyzed retrospectively. According to results of ultrasonic diagnosis of fetus, they were divided into isolated group (n=1 017, fetus with increased NT thickness only) and combined group (n=244, fetus with increased NT thickness and others structural malformation). Among them, there were 1 164 fetus who received interventional prenatal diagnosis to identify occurrence of fetus with chromosomal abnormalities or not. According to isolated group and combined group they belonged to, they were divided into isolated subgroup (n=965) and combined subgroup (n=199). Chi-square test were used to compare differences of incidence of fetus chromosomal abnormalities between isolated subgroup and combined subgroup, also between these two subgroups in different levels of NT thickness. The procedure followed in this study was consistent with World Medical Association Declaration of Helsinki revised in 2013.

① The top three of others ultrasonic structural malformations which combined in combined group of 244 fetuses were 45 cases (18.4%) of cystic hygroma, 44 cases (18.0%) of heart malformations and 23 cases (9.4%) of exomphalos. ② For cases who received interventional prenatal diagnosis, the incidence of chromosomal abnormality in combined subgroup was 52.8% (105/199), which was significantly higher than that of 16.9% (163/965) in isolated subgroup, and the differences was statistically significant (χ²=123.900, P<0.001). ③ For cases who received interventional prenatal diagnosis, when NT values were 3.0-3.9 mm, 4.0-4.9 mm, 5.0-5.9 mm, ≥6.0 mm, the incidence of chromosomal abnormality in combined subgroup were 34.8%, 60.9%, 56.3%, 67.3%, which were significantly higher than those of 10.8%, 20.9%, 31.4%, 42.9% in isolated subgroup, and the differences were statistically significant (χ²=31.400, P<0.001; χ²=29.453, P<0.001; χ²=5.676, P=0.028; χ²=6.854, P=0.014).

The fetus is at greater risk of chromosomal abnormality when it is with increased NT thickness combined with others structural malformations, or with NT value ≥6.0 mm at first trimester. Once fetus with increased NT thickness is found at first trimester, their heart structure screening should be taken.