高龄孕妇有创产前诊断胎儿染色体核型结果分析

目的:通过回顾分析4429例高龄孕妇的胎儿染色体核型结果,探讨高龄孕妇的产前诊断和产前筛查方法。方法:选取单纯因高龄、高龄合并血清学筛查高风险和高龄合并超声提示异常于盛京医院产前诊断中心行有创产前诊断的单胎妊娠孕妇共4429例,分析胎儿染色体核型结果。结果:胎儿非多态性染色体异常170例,异常率为3.84%(170/4429),其中数目异常95例,占核型异常的55.88%(95/170);结构异常23例,占核型异常的13.53%(23/170);嵌合体52例,占核型异常的30.59%(52/170)。合并血清学筛查高风险组与单纯高龄组相比,数目异常发生率有升高趋势,但差异无统计学意义(P0.05)。合并超声提示异常组与单纯高龄组相比,数目异常发生率有明显升高趋势,差异有统计学意义(P0.05)。随着年龄段的升高,染色体数目异常发生率明显增高,差异有统计学意义(P0.05)。伴有超声异常的高龄孕妇其胎儿染色体数目异常发生率随年龄升高更加明显,差异有统计学意义(P=0.001)。结论:孕期超声检查对高龄孕妇唐氏儿筛查十分重要,合并超声提示异常的高龄孕妇其胎儿染色体异常发生率明显升高,建议行有创产前诊断。     

598例妊娠中晚期胎儿超声异常与染色体异常的关系

目的:探讨妊娠中、晚期胎儿超声异常时染色体异常情况,以指导脐血穿刺的选择。方法:对我院胎儿超声异常的598例妊娠中、晚期孕妇取脐血进行染色体检查,分析胎儿超声结构异常及超声软指标异常的异常染色体检出率及异常染色体分类。结果:598例孕妇中,染色体异常61例,检出率10.20%,其中三体儿42例,占染色体异常的68.85%;超声结构异常胎儿染色体异常检出率明显高于超声软指标异常胎儿(P0.05);2项、3项及以上超声软指标异常染色体异常检出率明显高于单项软指标异常胎儿(P0.05);鼻骨缺失染色体异常检出率41.67%,单脐动脉染色体异常检出率12.24%;超声异常合并高龄孕妇组染色体异常检出率明显高于合并低孕龄组(P0.05);超声异常合并羊水过多组异常染色体检出率明显高于合并羊水正常组(P0.05)。结论:当有胎儿超声结构异常、超声软指标鼻骨缺失、两项及以上软指标异常、超声软指标异常合并高龄或羊水过多的情况时,染色体异常发生率明显增加,建议行脐血管穿刺染色体检查。     

颈部透明层增厚与染色体异常的相关分析

目的:评估颈部透明层(NT)增厚胎儿的染色体异常风险,探讨染色体微阵列分析(CMA)在NT增厚时的应用情况。方法:回顾性分析374例于广州医科大学附属第三医院诊断为NT增厚胎儿的超声及CMA结果。结果:374例NT增厚病例中,109例(29.1%)染色体异常。在NT值为2.5～3.4 mm、3.4～4.4 mm、4.5～5.4 mm、≥5.5 mm 4组中每组病例数及染色体异常例数分别为114例,26例(22.8%);150例,33例(22.0%);55例,19例(34.5%);55例,31例(56.4%)。各NT值组染色体异常比较差异有统计学意义,NT增厚的程度与胎儿发生染色体异常正相关(ρ=0.208,P0.001)。NT增厚且合并其他超声异常者共64例,染色体异常率为60.9%(39/64),与单纯NT增厚胎儿染色体异常率(22.6%)比较,差异有统计学意义(χ~2=37.794,P0.001)。结论:早孕期胎儿NT增厚与染色体异常、其他超声异常密切相关;NT增厚的程度越大,胎儿发生染色体异常的风险越高。与单纯NT增厚胎儿相比,合并其他超声异常的胎儿染色体异常检出率更高。     

妊娠早期胎儿颈部透明层厚度与胎儿预后的前瞻性队列研究

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4958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4791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4791例孕妇,包括胎儿NT厚度正常且无结构异常者4726例,其中妊娠中期及产后新诊断结构异常83例,4688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(χ2=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(χ2=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。     

1 658例颈项透明层增厚胎儿基因组拷贝数变异检测结果及出生结局

目的总结颈项透明层(nuchal translucency, NT)增厚胎儿的遗传学病因和预后, 以指导产前咨询和诊断。方法回顾性纳入2014年8月至2021年12月于河南省人民医院因早孕期胎儿NT≥2.5 mm而接受介入性产前诊断[染色体核型分析和/或染色体微阵列分析或拷贝数变异(copy number variation, CNV)测序]的非高龄单胎妊娠孕妇(n=1 658)。依据NT厚度(≥2.5～<3.0、≥3.0～<3.5、≥3.5～<4.5、≥4.5～<5.5、≥5.5～<6.5和≥6.5 mm组)和胎儿超声异常进行分组(孤立性NT增厚组、NT增厚合并软指标/非重大结构异常组和NT增厚合并重大结构异常组), 比较不同组间介入性产前诊断结果及出生结局。采用χ2检验和趋势χ2检验进行统计学分析。结果以2.5 mm或3.0 mm为NT增厚切割值时, 胎儿染色体数目异常检出率分别为15.8%(262/1 658)和17.6%(252/1 431)。染色体数目异常检出率随NT增厚而升高(χ2趋势=180.75, P<0.001), 由NT≥2.5～...     

胎儿颈项透明层增厚和静脉导管血流频谱异常与胎儿染色体异常的关系

目的探讨胎儿颈项透明层(nuchal translucency, NT)超声检查在早孕期胎儿筛查中的应用价值。 方法收集104例于广州市妇女儿童医疗中心诊断NT增厚的孕妇的染色体核型分析资料,回顾性分析胎儿NT增厚、静脉导管血流频谱异常与胎儿染色体异常的关系。 结果(1)9980例孕妇中,NT异常增厚的胎儿共104例,占1.0%,颈项透明层厚度为(3.7±1.2)mm;(2)104例NT异常增厚的胎儿中,有28例胎儿染色体核型异常,包括染色体数目异常22例,结构异常6例,其中前3位为21-三体综合征、18-三体综合征和47,XXX;(3)随着NT厚度的增加,染色体异常的检出率相应增加;(4)NT增厚及静脉导管血流频谱正常预测染色体异常的阳性预测值是20.93%,NT增厚及静脉导管血流频谱异常的阳性预测值是55.56%,其差异具有统计学意义( χ²＝7.07,P<0.01)。 结论在早孕期进行胎儿NT超声检查,NT增厚及静脉导管血流频谱异常联合筛查更能有效筛查出染色体核型异常的高危胎儿。     

189例唐氏综合征产前超声表现的临床特征

目的:总结189例唐氏胎儿的超声表现,分析结构畸形及软指标发生率。方法:回顾分析2010年至2016年在我院确诊为唐氏胎儿的超声结果。将超声指标分为无异常、孤立性软指标异常、结构畸形合并软指标异常、单纯结构畸形(包括单一系统结构畸形及多系统结构畸形)。结果:157例(83%,157/189)超声结果阳性,其中93例(49.2%,93/189)孤立性软指标异常,39例(20.6%,39/189)结构畸形合并软指标异常,25例(13.2%,25/189)为单纯结构畸形。64例(40.8%,64/157)结构畸形中有49例(76.6%,49/64)为单一系统结构畸形,11例(17.2%,11/64)为多系统结构畸形,4例(6.2%,4/64)为单发其他异常。结构畸形中常见的是心血管系统畸形(35.9%,23/64)。早孕期最常见的超声软指标异常是颈后透明层(NT)增厚(71.7%,43/60),鼻骨发育异常(40%,24/60);中孕期检出的超声软指标主要是颈后皮肤(NF)增厚(14.5%,19/131),鼻骨发育异常(27.5%,36/131)。结论:唐氏综合征胎儿以单系统结构畸形为主;早中孕期软指标分别以NT增厚、鼻骨发育不良和鼻骨缺如、NF增厚为主。     

NT超声检查在早孕期胎儿畸形筛查中的应用价值

目的 探讨胎儿颈项透明层厚度（NT）超声检查在早孕期胎儿畸形筛查中的应用价值。方法 选取500例行产前检查孕妇,均进行NT超声检查及唐氏筛查。通过筛查结果对比唐氏筛查与NT超声检查的胎儿颈部透明层厚度、胎儿畸形情况及胎儿畸形筛查率。结果 胎儿正常颈部透明层厚412例,胎儿异常颈部透明层厚度88例,胎儿正常颈部透明层厚度明显低于胎儿异常颈部透明层厚度,差异有统计学意义（P<0.05）;唐氏筛查筛查出的胎儿畸形结果为57例,少于NT超声检查筛查出的胎儿畸形结果81例。NT超声检查的胎儿畸形筛查率为16.2%,唐氏筛查的胎儿畸形筛查率为11.4%,唐氏筛查的胎儿畸形筛查率显著低于NT超声检查,差异有统计学意义（P<0.05）。结论 在早孕期中进行NT超声检查能够及时发现胎儿NT增厚、染色体异常、中枢神经系统异常等胎儿畸形情况,提高早孕期胎儿畸形筛查率,在一定程度上提高了超声诊断水平,具有良好的社会效应,值得临床推广与应用。     

925例高龄孕妇介入性产前诊断结果分析

目的 探讨不同产前诊断指征、不同年龄阶段的高龄孕妇胎儿染色体异常的发生情况,并对临床意义不明确的拷贝数变异(variant of uncertain significance, VUS)病例进行家系验证、随访妊娠结局,为高龄孕妇的临床遗传咨询提供参考依据。方法 选取2019年至2021年在乌鲁木齐市妇幼保健院行胎儿染色体核型分析和CMA检测的高龄孕妇共925例,按不同的产前诊断指征及年龄段进行分组比较,分析每组胎儿染色体异常的发生情况,并对VUS病例进行家系验证及随访。结果 925例孕妇中共检出胎儿染色体核型异常者124例(13.41%),包括染色体非整倍体异常80例(8.65%),其中单纯高龄组4例,高龄合并超声异常组27例,高龄合并无创DNA高风险组46例,高龄合并不良孕产史组2例,高龄合并夫妇一方染色体易位携带者1例,检出胎儿染色体结构异常44例。孕妇年龄介于35～40岁之间胎儿染色体非整倍体异常的发生率为7.25%,≥40岁时胎儿染色体非整倍体发生率为11.14%,P<0.05。共报告63例VUS,30例进行家系验证其中16例来源于父母,2例新发突变病例引产,其余随访时未...     

6047例高龄孕妇胎儿染色体核型结果分析

目的:分析高龄孕妇中不同年龄阶段及其他高危因素孕妇发生胎儿染色体异常的特点,以探讨针对单一年龄因素高龄孕妇的产前筛查及诊断策略。方法:本研究收集近三年在首都医科大学附属北京妇产医院产前诊断中心进行产前诊断的高龄孕妇(预产期年龄≥35岁)的临床资料,共6047例,分为4组:A组预产期年龄≤40岁,无其他高危因素;B组预产期年龄≤40岁,存在其他高危因素;C组预产期年龄>40岁,无其他高危因素;D组预产期年龄>40岁,存在其他高危因素。针对胎儿染色体核型分析结果进行回顾性研究。结果:①胎儿染色体异常的总发生率为6.10%,其中非整倍体为4.10%[21三体综合征(T21)为2.30%,18三体综合征(T18)为0.79%,性染色体数目异常为0.94%,13三体综合征(T13)为0.07%],染色体结构异常为1.97%。②A组染色体非整倍体异常(包括T21、T18、性染色体数目异常)及染色体结构异常与B组比较差异均有统计学意义(P<0.01,P<0.05);A组与C组的T21、T18、性染色体数目异常比较,差异有统计学意义(P<0.01,P<0.05),两组染色体结构异常发生率比较差异无统计学意义(P>0.05);B组与D组的T21、T18、性染色体数目异常、染色体结构异常发生率差异无统计学意义(P>0.05);C组与D组的T18、性染色体数目异常、染色体结构异常发生率差异无统计学意义(P>0.05),两组间T21发生率差异有统计学意义(P<0.05)。③单纯高龄因素的孕妇与非单纯高龄因素的孕妇比较,胎儿染色体异常的发生率前者明显低于后者,其发生率随着年龄的增加而呈现逐渐交汇的趋势;而胎儿染色体结构异常的发生率比较,两组间差异无统计学意义。结论:当存在单独年龄因素时,预产期年龄≤40岁的孕妇,其发生胎儿非整倍体异常的风险显著低于预产期年龄>40岁的孕妇,也低于具有其他产前诊断高危因素的人群,采用恰当的产前筛查技术有助于提高此类人群的产前诊断效率。     

Diagnostic methods for fetal malformations in the first half of pregnancy

INTRODUCTION: Fetal abnormalities are the most common cause of perinatal and postnatal death and infant handicap. For this reason prenatal screening (for fetal malformation) has become a routine part of obstetric care in many countries. Most often used are biochemical tests and continuously developing ultrasound diagnostics which makes possible precise analysis of the fetal morphology. There is interesting to establish a noninvasive test for the early detection of fetal malformation in pregnancy which is based on ultrasound examination (NT measurement from the 10th to the 19th weeks, presence of nasal bone in the first trimester ultrasound), correlated with serum concentration of AFP, beta-HCG and oestriol in the second trimester of pregnancy (triple test). The main aim of the study was to establish a diagnostic schema for detection of fetal malformations based on NT measurement in the first and second trimester coupled with triple test performed in the second trimester. MATERIALS AND METHODS: A group of 775 pregnant women from the 10-th week of pregnancy until childbirth has been put under examination. Between the 10th and the 14th and than between 15th and 19th week of pregnancy ultrasound examination with fetal biometry and NT measurement was done. NT measurements have been performed in accordance with the standards worked out by professor K. Nicolaides. At the first ultrasound examination the presence of the nasal bone was observed. The next step was performing the triple test between the 15th and 19th week of pregnancy. On the same day as second ultrasound examination blood was taken to determine the results of the triple test (ELISA method). The obtained results have undergone statistical analysis. RESULTS: The age of women qualified for the examination oscillated between 15 and 45 (over 35 -9.4%). There were 8 fetal malformations recognized all connected with the chromosomal anomalies, namely, 4 Downs syndrome, 2 fetuses with trisomy of the 18th pair of chromosomes and 2 with triploidy. At all physiologic pregnancies nasal bone was seen during first ultrasound examination. The obtained results of nuchal fold measurements and concentrations for the parameters of the triple test have been the basis to calculate medians in the particular weeks of pregnancy. In all the cases of genetic malformations the widening of the nuchal fold above 99 percentile (MoM NT) has been observed. Fetal nasal bone were absent in 62.5% first trimester ultrasound examinations. The risk of the occurrence of a genetic malformation resulting from the mother's age combined with the risk connected with the NT measurements and the results of the triple test for the cut-off point 1:250 (which seems to be the best for this population) gave 100% sensitivity, 0.6% % of false positive results and the positive predictive value of 80%. The above mentioned results are better than the ones which were obtained within the triple test only, where for the previously fixed cut-off point 1:250 sensitivity reached 63%, positive predictive value 25% and 4.4% false positive rate. Performing the so-called integrated test in which the risk of the occurrence of any malformation is estimated on the basis of the NT measurement in the first and the second term of pregnancy seems to be far more useful. CONCLUSIONS: Diagnostic schema for detection of fetal malformations in the first half of pregnancy which is based on ultrasound examination (NT measurement from the 10th to the 19th weeks), correlated with serum concentration of AFP, beta-HCG and oestriol in the second trimester of pregnancy (triple test) is very sensitive and safe method of the prenatal diagnosis leading to significant decrease of the invasive procedures (amniocentesis).     

Absence of fetal nasal bone and aneuploidies at first-trimester nuchal translucency screening in unselected pregnancies

OBJECTIVES: The absence of nasal bone (NB) has been noted in trisomy 21 fetuses at first-trimester ultrasound, in high-risk pregnancies. In this study, the nasal bone was evaluated in relation to fetal karyotype, in unselected pregnancies. METHODS: From September 2001 to September 2002, the fetal facial profile was examined at the 11 to 14 weeks' scan for screening by nuchal translucency (NT). Risks for trisomy 21 were calculated using the Fetal Medicine Foundation's software, and the presence or absence of NB was noted. Prenatal karyotype and pregnancy outcomes were recorded. RESULTS: NT screening was performed in 5532 fetuses from 5425 pregnancies (85 twins, 8 triplets, 2 quadruplets). The visualization of fetal profile was obtained in 5525 fetuses (99.8%), and in 5491 fetuses (99.4%) the NB was present and in 34 cases (0.6%) it was absent. Fetal karyotype and pregnancy outcome were available in 3503 pregnancies, and 40 chromosomal abnormalities were diagnosed (27 trisomies 21, 5 trisomies 18, 2 trisomies 13, 3 Turner syndromes, 1 partial trisomy 9 and 2 others). The NB was absent in 19 (70%) trisomies 21, 4 trisomies 18 (80%), 2 Turner syndromes (66%), in the partial trisomy 9, in 7 normal karyotype fetuses (0.2%), and in a case with spontaneous first-trimester abortion before prenatal diagnosis. A significant difference was found between NT thickness, expressed as a multiple of the median, in trisomy 21 fetuses with present and absent nasal bone. CONCLUSIONS: The absence of NB at 11 to 14 weeks is more frequent in fetuses with trisomy 21 and other aneuploidies than in normal karyotype fetuses.     

146例非免疫性水肿胎儿的产前染色体分析

目的:分析非免疫性水肿胎儿的产前诊断结果,明确其染色体异常的类型。方法:选取146例非免疫性水肿胎儿,通过经腹绒毛取样、羊膜腔穿刺、脐静脉穿刺及流产后取胎儿组织送检的方法进行胎儿染色体核型及低覆盖度大规模平行测序技术(CNV-seq)的分析。结果:146例胎儿的染色体异常发生率为48.6%(71/146),其中性染色体异常29例,21-三体19例,18三体13例,13-三体3例,其他染色体异常1例,致病性拷贝数变异6例。染色体异常检出率随着孕周的增加而降低,<14孕周、14~27孕周、≥28孕周孕妇的染色体异常检出率分别为68.4%(39/57)、40.8%(31/76)和7.7%(1/13)。水肿胎儿最常合并的超声结构异常依次为NT/NF增厚、颈部水囊瘤及心脏异常,其染色体异常检出率分别为59.5%、59.2%及51.9%。结论:染色体异常是胎儿水肿的常见病因,特别是早中孕期出现水肿的胎儿,检出率较高。对于水肿胎儿的产前诊断,除了常规的核型以外,需重视拷贝数变异的检测。     

Fetal nasal bone and trisomy 21 in the second trimester

OBJECTIVES: To assess the feasibility of measuring nasal bone length in the second trimester of pregnancy and to confirm if fetal nasal bone absence or hypoplasia is a marker for Down syndrome. METHODS: Fetal nasal bone assessment was performed in 439 consecutive singleton pregnancies at high risk of Down syndrome between 15 and 21 weeks. All ultrasound examinations were performed transabdominally by five skilled sonographers. If the nasal bone was present, its length was measured. The biparietal diameter: nasal bone length ratio (BPD/NBL) was also calculated. RESULTS: Nasal bone assessment was successfully achieved in all fetuses. The nasal bone was absent in 2(0.47%) of the 417 unaffected fetuses and in 10(55.5%) of the 18 fetuses with trisomy 21. Of the 8 Down syndrome cases with a nasal bone present, 4 had nasal bone hypoplasia and 4 had a normal nasal bone. BPD/NBL was 9 or greater in 7 of the 8 fetuses affected by trisomy 21 with nasal bone present and in 86 (20.6%) of the 417 normal fetuses; it was 10 or greater in 5 of the 8 (62.5%) fetuses affected by trisomy 21 and in 41 of the 417 (9.8%) euploid fetuses. CONCLUSIONS: Nasal bone absence is a marker for Down syndrome in the second trimester of pregnancy. Inclusion of nasal bone length into the second-trimester screening protocol could potentially obviate the false-negative cases from other screening tests. The measurement of nasal bone length in the second trimester seems to provide additional benefits beyond the assessment of the presence or absence of the nasal bone.     

Sonographic Markers of Fetal Aneuploidy—A Review

The most effective sonographic marker of trisomy 21 and other chromosomal defects is increased nuchal translucency (NT) thickness at 11–14 weeks. Extensive studies over the last decade have examined the methodology of measuring NT, the development of the necessary algorithms for calculating the individual patient risk for trisomy 21 by NT in combination with maternal age and with various maternal serum biochemical markers, and the performance of this test. Another promising marker for trisomy 21, both in the first and second trimesters, is absence of the fetal nasal bone. There is also an extensive literature on the association between chromosomal abnormalities and a wide range of second trimester ultrasound findings. However, there are very few reports that have prospectively examined the screening performance of second trimester markers. This article reviews the association between sonographically detectable fetal abnormalities and chromosomal defects, and examines the value of incorporating these defects in screening policies.     

247例妊娠中期孕妇羊水细胞染色体核型分析

目的 分析妊娠中期进行产前诊断的孕妇羊水细胞染色体核型，了解此期异常核型发生的频率、类型及与各种产前诊断指征的关系。方法 对247例妊娠中期孕妇行羊膜腔穿刺术抽羊水作羊水细胞培养检查染色体核型。结果 发现异常核型14例，异常核型出现频率为5．67％，其中三体型7例，占异常核型的50％，分别为21三体4例，18三体2例，13三体1例；其次为平衡易位6例，占42．86％。高龄孕妇中21三体检出率为5．56％(1／18)，非高龄组为1．31％(3／229)，P=0．235，差异无显著性。15例产前常规B超检查发现胎儿发育异常的孕妇中，检出三体儿3例。结论 在有各种产前诊断指征的妊娠中期孕妇中，胎儿染色体异常发生率为5．67％，染色体三体为主要的异常核型。孕中期B超检查做为产前常规筛查可提高胎儿染色体异常的检出率。     

First-trimester screening for chromosomal abnormalities

There is extensive evidence that effective screening for major chromosomal abnormalities can be provided in the first trimester of pregnancy. Randomized studies have established that the risk of miscarriage from chorionic villus sampling in the first trimester is the same as for amniocentesis in the second trimester. Prospective studies have demonstrated that screening by a combination of fetal nuchal translucency (NT) and maternal serum free-beta-human chorionic gonadotropin (hCG) and pregnancy-associated plasma protein-A (PAPP-A) can identify 90% of fetuses with trisomy 21 and other major chromosomal abnormalities for a false-positive rate of 5%. This is superior to the 30% detection rate achieved by maternal age and 65% by second-trimester maternal serum biochemistry. A further improvement in the effectiveness of first-trimester screening is likely to be achieved by a risk-orientated two-stage approach. In this, the patients are subdivided into a high-risk group, requiring invasive testing, a low-risk group, which can be reassured that an abnormality is unlikely, and an intermediate-risk group (risk of 1 in 101 to 1 in 1000), in which further assessment is performed by first-trimester ultrasound examination (for presence/absence of the nasal bone or presence/absence of tricuspid regurgitation or normal/abnormal Doppler velocity waveform in the ductus venosus), and chorionic villus sampling is performed if their adjusted risk becomes 1 in 100 or more. As with all aspects of good clinical practice, those performing first-trimester scans should be appropriately trained and their results subjected to external quality assurance. This process was well established by the Fetal Medical Foundation several years ago and is widely accepted internationally.     

9例多胎妊娠合并胎儿染色体异常患者的产前诊断和治疗

目的探讨多胎妊娠合并胎儿染色体异常的产前诊断方法及选择性减胎术定位方法。 方法选取2012年1月至2013年12月就诊于广州医科大学附属第三医院9例多胎妊娠合并胎儿染色体异常患者的临床资料,采用回顾性研究方法对其产前诊断方法、染色体异常情况、选择性减胎术的方法及妊娠结局进行分析。 结果9例患者中3例为三胎妊娠,6例为双胎妊娠。(1)产前诊断：①超声检查：9例患者早孕期行超声检查,均提示存在胎儿颈项透明层(nuchal translucency, NT)增厚,孕中期超声检查提示有6例患者存在胎儿结构异常,包括颈部囊肿、心脏异常、外生殖器畸形、足内翻、全身水肿等;②染色体检查：5例胎儿21-三体综合征,1例Turner综合征,1例染色体微缺失,1例染色体重复,1例双胎染色体异常。(2)治疗及妊娠结局：9例患者中7例患者行选择性减胎术治疗,1例流产,3例早产(新生儿均存在并发症),3例足月分娩(新生儿均未见异常);2例患者拒绝减胎,1例于孕中期自然流产,1例于孕35^＋周剖宫产分娩(1胎儿为21-三体综合征,另一胎儿为健康儿)。 结论多胎妊娠应注重早孕期染色体筛查,确诊宫内胎儿染色体异常的患者可在超声引导下行选择性减胎术治疗。     

First trimester genetic sonogram for screening fetal Down syndrome: A population-based study

ObjectiveTo evaluate the performance of first trimester sonomarkers in the detection of fetal Down syndrome among Thai pregnant women.Materials and methodsPregnant women at 11–13⁺⁶ weeks’ gestation underwent ultrasound examination for assessment of nuchal translucency (NT), nasal bone (NB), tricuspid regurgitation (TR), and abnormal ductus venosus (aDV) Doppler waveforms. The women were followed up for final outcomes. Fetal abnormalities other than trisomy 21 were excluded. The performances of each sonomarker and their combinations in predicting fetal Down syndrome were calculated.ResultsA total of 7820 pregnant women meeting the inclusion criteria were available for analysis, including 20 cases with fetal Down syndrome and 7800 unaffected cases. Of the four sonomarkers, NT, as a single sonomarker, had the highest detection rate (55.0% at a false positive rate of about 5%), whereas the remaining single sonomarkers had low detection rate (15–20%). The combination of all sonomarkers had the highest detection rate of 70% but the false positive rate was as high as 10.8%. The combination of NT and NB had a detection rate of 60% with an acceptable false positive rate of 6.9%, whereas the other combinations yielded relatively high false positive rates.ConclusionThe first trimester genetic sonogram in screening for Down syndrome among Asian women is acceptably effective and may be offered to some selected groups of the population. NT is the best sonomarker with a detection rate of 55% at 5% false positive rate and its combination with NB can improve performance with minimal increase in false positive rate.