Objective: To explore the relationship between fetal nuchal translucency (NT) in the first trimester and pregnancy outcome. Methods: A prospective cohort study was conducted in Nanjjing Drum Tower Hospital from December 2015 to December 2018, 4 958 singleton pregnant women were enrolled to screen fetal ultrasound structure and serology in the first trimester, ultrasound in the second trimester and neonatus physical examination 28 days after birth. According to the results of NT, 167 cases of fetus with increased NT (≥3.0 mm) and 4 791 cases of normal NT were divided, moreover, 86 cases with isolate increased NT and 81 cases of increased NT combined with structural abnormality. The prognosis of fetuses with different NT thickness was analyzed, and the pregnancy outcome of fetuses with isolate increased NT or combined with structural abnormality were analyzed. In the first trimester, if the fetal structure was abnormal or the serological screening result was high risk, the chromosomal microarray analysis (CMA) would be performed by chorionic villus sampling to determine the prenatal diagnosis. Results: (1) The pregnancy outcome for fetus of normal NT: there were 4 791 cases with normal NT. Totally, 4 726 cases with normal NT and no structural abnormalities were screened out in the firsttrimester. In this group, 5 cases of aneuploidies were diagnosed based on high risk of maternal serum biomarkers and 83 cases of structural abnormalities were screened out in the subsequent ultrasound scan and the neonatal examination. Another 65 cases with normal NT present complicated with structural anomalies were screened out in the first trimester and 4 cases were diagnosed as aneuploidies. (2) The pregnancy outcome for fetus of isolate increased NT: 66 (76.7%, 66/86) cases of isolated increased NT were performed CMA, 3 cases were diagnosed as trisomy 21 and terminated pregnancy. Another 4 cases were terminated pregnancy privately without cytogenetic diagnosis. No further anomalies were found in 79 cases till 6 to 21 months postnatally. (3) The pregnancy outcome for fetus of increased NT with structural anomalies: increased NT present with structural anomalies were screened out by detailed anomaly scan in the first trimester and 32 of them were confirmed as aneuploidies. In this group, 70 cases terminated pregnancy, 2 cases had spontaneous miscarriages and 9 cases had liveborns (1 newborn was found ventricular septal defect). (4) The pregnancy outcome for fetus of increased NT with or without structural anomalies: the percentage of aneuploidies in fetuses with isolated increased NT (3.5%, 3/86) was significantly lower than those with structural abnormalities (39.5%,32/81). The healthy survival rate in fetuses with isolated increased NT (91.9%,79/86) was significantly higher than those with structural abnormalities (9.9%, 8/81). Conclusions: A detailed first-trimester anomaly scan could improve prenatal screening efficiency of birth defects. Compared to the fetuses with increased NT combined with structural abnormalities, the healthy survival rate of fetuses with isolated increased NT based on detailed first-trimester anomaly scan is higher and the percentage of fetal aneuploidies is lower.
目的： 探讨妊娠早期胎儿颈部透明层（NT）厚度与胎儿预后的关系。 方法： 收集2015年12月至2018年12月于南京大学医学院附属鼓楼医院行妊娠早期胎儿NT厚度测量的单胎孕妇，共4 958例建立前瞻性研究队列，进行妊娠早期胎儿结构超声筛查、妊娠早期血清学筛查、妊娠中期超声筛查及对新生儿出生后28 d的体格检查。根据妊娠早期超声筛查的结果，分为胎儿NT增厚（≥3.0 mm）者167例与NT厚度正常者4 791例；将胎儿NT增厚的孕妇，分为胎儿单纯NT增厚者86例与NT增厚合并结构异常者81例。分析不同NT厚度胎儿的预后，并重点对单纯NT增厚与NT增厚合并结构异常胎儿的妊娠结局进行分析。妊娠早期超声筛查发现胎儿结构异常或血清学筛查结果为高风险的孕妇，经绒毛穿刺取样术行染色体微阵列分析（CMA）检测以明确产前诊断。 结果： （1）胎儿NT厚度正常孕妇的妊娠结局：共4 791例孕妇，包括胎儿NT厚度正常且无结构异常者4 726例，其中妊娠中期及产后新诊断结构异常83例，4 688例活产；胎儿NT厚度正常但结构异常的孕妇65例，其中61例孕妇终止妊娠，4例活产。（2）胎儿单纯NT增厚孕妇的妊娠结局：86例孕妇中，66例（76.7%，66/86）行CMA检测，3例胎儿诊断为21三体综合征；除7例孕妇选择终止妊娠外，余79例行妊娠中期超声检查、新生儿出生后28 d体格检查、新生儿电话随访至6~21个月均未发现发育异常。（3）胎儿NT增厚合并结构异常孕妇的妊娠结局：81例孕妇中，73例（90.1%，73/81）行CMA检测，其中32例的胎儿为染色体非整倍体异常。70例选择终止妊娠，2例妊娠中期自然流产，9例活产。（4）NT增厚是否合并结构异常胎儿的产前诊断结果及预后比较：单纯NT增厚的胎儿染色体非整倍体的发生率为3.5%（3/86），合并结构异常者为39.5%（32/81），两者比较，差异有统计学意义（χ(2)=32.7，P<0.01）；胎儿单纯NT增厚孕妇的健康新生儿存活率为91.9%（79/86），合并结构异常者为9.9%（8/81），两者比较，差异有统计学意义（χ(2)=112.3，P<0.01）。 结论： 妊娠早期，超声筛查胎儿NT及结构，能提高出生缺陷的产前筛查率。单纯NT增厚胎儿的染色体非整倍体的发生率较低，新生儿健康存活率较高。.
Keywords: Aneuploidy; Cohort studies; Nuchal translucency measurement; Pregnancy trimester, first; Ultrasonography, prenatal.