BACKGROUND

Down syndrome or trisomy 21, the most common chromosomal disorder, results from the presence of a third copy of chromosome 21 and manifests as mild to moderate intellectual disability, growth retardation, congenital heart defects, gastrointestinal abnormalities, and characteristic facial features. Several methods have been used to screen for Down syndrome in the prenatal period, such as ultrasound, biomarkers, cell-free DNA testing, and combinations of these tests. A positive result from one or more of these screening tests signals the need for confirmatory karyotyping to clinch the diagnosis. Ultrasound between 11 to 14 weeks of gestation can evaluate nuchal translucency (NT) to screen for Down syndrome. During the second trimester, a triple or quadruple test can also be performed alone or in addition to NT to quantify Down syndrome risk. In limited resource settings however, only the measurement of NT via ultrasound can be performed since biomarker tests are either unavailable or inaccessible. While the diagnostic performance of NT measurement alone has been investigated in several observational studies, there is no consensus on its performance as a sole test to screen for Down syndrome.

To determine the diagnostic performance of NT during prenatal first-trimester ultrasound as a screening test for Down syndrome.

We performed a systematic search on the PubMed, ProQuest, and Cochrane Library databases for recent systematic reviews and meta-analyses that addressed the objective. The existing reviews found were then independently appraised by the two reviewers with the AMSTAR-2 checklist. To update the existing reviews, a systematic search was done in the same databases to identify additional primary diagnostic studies, which were appraised using the QUADAS-2 tool. Random-effects univariate meta-analysis and summary receiving operator curve (HSROC) analysis for the outcomes were performed using Review Manager version 5.4 and R version 4.2.2, respectively. Subgroup analysis was performed by stratifying the baseline risk of mothers for fetal anomaly as low- or high-risk. Highrisk mothers were defined as women with risk factors such as advanced age, positive serum screen, presence of other ultrasound anomalies, and history of previous fetus with anomaly.

We found 22 cohort studies (n=225,846) of women at low-risk for fetal anomaly. The pooled sensitivity was 67.8% (95% CI: 61.4%-73.6%, I2=70.4%) and specificity was 96.3% (95% CI: 95.5%-96.9%, I2=96.7%). For low-risk women, the overall certainty of evidence was low, due to different modes of verification and heterogeneity not completely explained by variability in baseline risk or cut-points. Seven studies (n=9,197) were on high-risk women. The pooled sensitivity was 62.2% (95% CI: 54.1%-69.7%, I2=38.8%) and specificity was 96.5% (95% CI: 93.6%-98.1%, I2=95.5%). For women at high-risk, the evidence was rated as moderate due to differential verification.

Our analysis showed that NT measured through first-trimester ultrasound is specific for Down syndrome but has low sensitivity. Despite this, it is a useful screening test for Down syndrome in low-resource settings where other strategies may not be available or accessible. Furthermore, interpretation of NT results must take into consideration its limited sensitivity as this may lead to missed cases.

BACKGROUND

Down syndrome or trisomy 21, the most common chromosomal disorder, results from the presence of a third copy of chromosome 21 and manifests as mild to moderate intellectual disability, growth retardation, congenital heart defects, gastrointestinal abnormalities, and characteristic facial features. Several methods have been used to screen for Down syndrome in the prenatal period, such as ultrasound, biomarkers, cell-free DNA testing, and combinations of these tests. A positive result from one or more of these screening tests signals the need for confirmatory karyotyping to clinch the diagnosis. Ultrasound between 11 to 14 weeks of gestation can evaluate nuchal translucency (NT) to screen for Down syndrome. During the second trimester, a triple or quadruple test can also be performed alone or in addition to NT to quantify Down syndrome risk. In limited resource settings however, only the measurement of NT via ultrasound can be performed since biomarker tests are either unavailable or inaccessible. While the diagnostic performance of NT measurement alone has been investigated in several observational studies, there is no consensus on its performance as a sole test to screen for Down syndrome.

To determine the diagnostic performance of NT during prenatal first-trimester ultrasound as a screening test for Down syndrome.

We performed a systematic search on the PubMed, ProQuest, and Cochrane Library databases for recent systematic reviews and meta-analyses that addressed the objective. The existing reviews found were then independently appraised by the two reviewers with the AMSTAR-2 checklist. To update the existing reviews, a systematic search was done in the same databases to identify additional primary diagnostic studies, which were appraised using the QUADAS-2 tool. Random-effects univariate meta-analysis and summary receiving operator curve (HSROC) analysis for the outcomes were performed using Review Manager version 5.4 and R version 4.2.2, respectively. Subgroup analysis was performed by stratifying the baseline risk of mothers for fetal anomaly as low- or high-risk. Highrisk mothers were defined as women with risk factors such as advanced age, positive serum screen, presence of other ultrasound anomalies, and history of previous fetus with anomaly.

We found 22 cohort studies (n=225,846) of women at low-risk for fetal anomaly. The pooled sensitivity was 67.8% (95% CI: 61.4%-73.6%, I2=70.4%) and specificity was 96.3% (95% CI: 95.5%-96.9%, I2=96.7%). For low-risk women, the overall certainty of evidence was low, due to different modes of verification and heterogeneity not completely explained by variability in baseline risk or cut-points. Seven studies (n=9,197) were on high-risk women. The pooled sensitivity was 62.2% (95% CI: 54.1%-69.7%, I2=38.8%) and specificity was 96.5% (95% CI: 93.6%-98.1%, I2=95.5%). For women at high-risk, the evidence was rated as moderate due to differential verification.

Our analysis showed that NT measured through first-trimester ultrasound is specific for Down syndrome but has low sensitivity. Despite this, it is a useful screening test for Down syndrome in low-resource settings where other strategies may not be available or accessible. Furthermore, interpretation of NT results must take into consideration its limited sensitivity as this may lead to missed cases.

Human ; Mass Screening ; Mothers ; Nuchal Translucency Measurement ; Prenatal Diagnosis

OBJECTIVE: To assess the value of chromosomal microarray analysis (CMA) and trio-whole exome sequencing (trio-WES) for fetuses with increased nuchal translucency (NT) thickness. METHODS: Sixty two pregnant women who had visited Urumqi Maternal and Child Care Health Hospital between June 2018 and June 2020 for NT ≥ 3.0 mm at 11 ~ 13⁺⁶ gestational weeks were selected as study subjects. Relevant clinical data were collected. The patients were divided into 3.0 ~ ＜3.5 mm (n = 33) and ≥3.5 mm groups (n = 29). Chromosome karyotyping analysis and chromosomal microarray analysis were carried out. And trio-WES analysis was performed on 15 samples with NT thickening but negative CMA results. The distribution and incidence of chromosomal abnormalities in the two groups were compared by using chi-square test. RESULTS: The median age of the pregnant women was 29 years old (22 ~ 41 years old), the median thickness of NT was 3.4 mm (3.0 ~ 9.1 mm), and the median gestational age at the detection was 13⁺⁴ weeks (11⁺⁵ ~ 13⁺⁶ weeks). Chromosome karyotyping analysis has detected 12 cases of aneuploidies and 1 case of derivative chromosome. The detection rate was 20.97% (13/62). CMA has detected 12 cases of aneuploidies, 1 case of pathogenic CNV and 5 cases of variant of uncertain significance (VUS), with a detection rate of 29.03% (18/62). The aneuploidy rate for the NT ≥ 3.5 mm group was higher than that for the 3.0 ≤ NT < 3.5 mm group [3.03% (1/33) vs. 41.38% (12/29), χ² = 13.698, P < 0.001]. There was no statistically significant difference between the two groups in the detection rate of fetal pathogenic CNV and VUS (χ² = 0.028, P > 0.05). Trio-WES analysis of 15 samples with negative CMA result and no structural abnormality has identified 6 heterozygous variants, including SOS1: c.3542C>T (p.A1181V) and c.3817C>G (p.L1273V), COL2A1: c.436C>T (p.P146S) and c.3700G>A (p.D1234N), LZTR1: c.1496T>C (p.V499A), and BRAF: c.64G>A (p.D22N), respectively. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), all of the variants were rated as VUS. CONCLUSION NT thickening can indicate chromosome abnormality, and CMA and trio-WES may be used for the prenatal diagnosis.
Pregnancy ; Humans ; Female ; Adult ; Infant ; Nuchal Translucency Measurement/methods* ; Prenatal Diagnosis/methods* ; Chromosome Aberrations ; Aneuploidy ; Fetus/diagnostic imaging* ; Ultrasonography, Prenatal ; DNA Copy Number Variations ; Transcription Factors

OBJECTIVE: To explore the genetic etiology of 5 cases of monochorionic-diamniotic (MCDA) with genetic discordance. METHODS: 148 cases of MCDA twins who were diagnosed by amniocentesis at the Maternal and Child Health Care Hospital of Guangxi Zhuang Autonomous Region from January 2016 to June 2020 were selected as the study subjects. Relevant clinical data of the pregnant women were collected, and amniotic fluid samples of the twins were collected separately. Chromosomal karyotyping analysis and single nucleotide polymorphism array (SNP array) assay were carried out. RESULTS: The results of chromosomal karyotyping analysis showed that 5 of the MCDA twins had inconsistent chromosome karyotypes, with an incidence of 3.4% (5/148). SNP array assay showed that 3 fetuses were mosaics. CONCLUSION Genetic discordance occurs among MCDA twins, and prenatal counseling for such cases should be given by doctors with experience in medical genetics and fetal medicine, and personalized clinical management should be recommended.
Child ; Pregnancy ; Female ; Humans ; China ; Twins/genetics* ; Amniocentesis ; Karyotyping ; Fetus ; Twins, Monozygotic/genetics* ; Ultrasonography, Prenatal ; Retrospective Studies

OBJECTIVE: To explore the prenatal ultrasonographic features and genetic basis for an abortus suspected for type II Cornelia de Lange syndrome (CdLS2). METHODS: A fetus diagnosed with CdLS2 at the Shengjing Hospital Affiliated to China Medical University on September 3, 2019 was selected as the study subject. Clinical data of the fetus and family history was collected. Following induced labor, whole exome sequencing was carried out on the abortus. Candidate variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: Prenatal ultrasonography (33 weeks of pregnancy) has revealed multiple anomalies in the fetus, which included slightly widened cavity of septum pellucidum, blurred corpus callosum, slightly reduced frontal lobe volume, thin cortex, fusion of lateral ventricles, polyhydramnios, small stomach bubble, and digestive tract atresia. Whole exome sequencing has revealed a heterozygous c.2076delA (p.Lys692Asnfs*27) frameshifting variant in the SMC1A gene, which was found in neither parent and was rated as pathogenic based on the guidelines of American College of Medical Genetics and Genomics (ACMG). CONCLUSION The CdLS2 in this fetus may be attributed to the c.2076delA variant of the SMC1A gene. Above finding has provided a basis for genetic counseling and assessment of reproductive risk for this family.
Pregnancy ; Female ; Humans ; Cell Cycle Proteins/genetics* ; De Lange Syndrome/diagnosis* ; Phenotype ; Ultrasonography, Prenatal ; Fetus/diagnostic imaging* ; Mutation

Objective: To retrospectively analyze the clinical data of different types of selective intrauterine growth restriction (sIUGR) pregnant women under expectant management, including the natural evolution, typing conversion and perinatal outcomes. Methods: The clinical data of 153 pregnant women with sIUGR under expected treatment in Women's Hospital, Zhejiang University School of Medicine from January 2014 to December 2018 were collected. Maternal characteristics including maternal age, gravidity, parity, method of conception, pregnancy complication, gestational age at delivery, indication for delivery, birth weight, the rate of intrauterine and neonatal death and neonatal outcomes were recorded. Pregnant women with sIUGR were divided into three types according to end-diastolic umbilical artery flow Doppler ultrasonography, and the differences of typing conversion and perinatal outcomes of sIUGR pregnant women based on the first diagnosis were compared. Results: (1) Clinical characteristics and pregnancy outcomes: among 153 pregnant women with sIUGR, 100 cases (65.3%) were diagnosed with type Ⅰ, 35 cases (22.9%) with type Ⅱ, and 18 cases (11.8%) with type Ⅲ. There were no significant differences in age, conception mode, pregnancy complications, first diagnosis gestational age, characteristics of umbilical cord insertion, delivery indications, fetal intrauterine mortality and neonatal mortality among three types of sIUGR pregnant women (all P>0.05). The average gestational age at delivery of type Ⅰ sIUGR was (33.5±1.9) weeks, which was significantly later than those of type Ⅱ and Ⅲ [(31.3±1.8), (31.2±1.1) weeks, P<0.001]. The percentage disordance in estimated fetal weight (EFW) of type Ⅰ sIUGR was significantly lower than those of type Ⅱ and type Ⅲ (P<0.001). The incidence rate of neonatal intensive care unit (NICU) admission, cerebral leukomalacia and respiratory complications of both fetus and necrotizing enterocolitis of large fetus in type Ⅰ were significantly lower than those in type Ⅱ and type Ⅲ (all P<0.05). (2) Typing conversion: in 100 cases of type Ⅰ sIUGR, 18 cases progressed to type Ⅱ and 10 cases progressed to type Ⅲ. Compared with 72 stable type Ⅰ sIUGR, those with progressed type Ⅰ sIUGR had higher incidence of NICU admission and lung disease in both fetuses, and cerebral leukomalacia and necrotizing enterocolitis in large fetus (all P<0.05). The proportion of inconsistent cord insertion was significantly higher in those type Ⅰ progressed to type Ⅲ (6/10) than in those with stable type Ⅰ (19.4%, 14/72) and type Ⅰ progressed to type Ⅱ sIUGR [0 (0/18), P=0.001]. Four cases of type Ⅱ sIUGR reversed to type Ⅰ and 6 cases reversed to type Ⅲ. Compared with type Ⅱ reversed to type Ⅰ sIUGR, those stable type Ⅱ and type Ⅱ reversed to type Ⅲ sIUGR had a higher incidence of NICU admission in large fetus (P<0.05). Two cases of type Ⅲ sIUGR reversed to type Ⅰ and 6 cases progressed to type Ⅱ. There were no significant differences in fetal serious complications in type Ⅲ sIUGR with or without doppler changes (all P>0.05). Conclusions: The different types of sIUGR could convert to each other. The frequency of ultrasound examinations should be increased for patients with the type Ⅰ sIUGR, especially when the percentage discordance in EFW is substantial or with discordant cord insersion.
Pregnancy ; Female ; Infant, Newborn ; Humans ; Fetal Growth Retardation/epidemiology* ; Pregnancy Outcome ; Retrospective Studies ; Enterocolitis, Necrotizing ; Twins, Monozygotic ; Umbilical Arteries/diagnostic imaging* ; Gestational Age ; Ultrasonography, Prenatal/methods* ; Pregnancy, Twin

Objective: To analysis the clinical characteristics of 400 fetuses with heart defects and the impactors of pregnancy decision making, and explore the influence of a multi-disciplinary team (MDT) cooperation approach on it. Methods: Clinical data of 400 fetuses with abnormal cardiac structure diagnosed at Peking University First Hospital from January 2012 to June 2021 were collected, which were divided into 4 groups according to the characteristics of fetal heart defects and the presence of extracardiac abnormalities or not: single cardiac defects without extracardiac abnormalities (122 cases), multiple cardiac defects without extracardiac abnormalities (100 cases), single cardiac defects with extracardiac abnormalities (115 cases), and multiple cardiac defects with extracardiac abnormalities (63 cases). The types of fetal cardiac structural abnormalities and genetic test results, and the detection rate of pathogenic genetic abnormalities, MDT consultation and management situation, and pregnancy decision of fetuses in each group were retrospectively analyzed. A logistics regression was used to analyze the influencing factors of fetal heart defects pregnancy decision. Results: (1) Among the 400 fetal heart defects, the four most common major types were ventricular septal defect 96 (24.0%, 96/400), tetralogy of Fallot 52 (13.0%, 52/400), coarctation of the aorta 34 (8.5%, 34/400), and atrioventricular septal defect 26 (6.5%, 26/400). (2) Among the 204 fetuses undergoing genetic examination, 44 (21.6%, 44/204) pathogenic genetic abnormalities were detected. (3) Detection rate of pathogenic genetic abnormalities (39.3%, 24/61) and pregnancy termination rate (86.1%, 99/115) in the single cardiac defects with extracardiac abnormalities group were significantly higher than those in the single cardiac defects without extracardiac abnormalities group [15.1% (8/53), 44.3% (54/122), respectively] and the multiple cardiac defects without extracardiac abnormalities group [6.1% (3/49), 70.0% (70/100), respectively, both P<0.05], and the pregnancy termination rate in the multiple cardiac defects without extracardiac abnormalities group and the multiple cardiac defects with extracardiac abnormalities group (82.5%,52/63) were significantly higher than that of the single cardiac abnormalities without extracardiac abnormalities group (both P<0.05). (4) After adjusting for age, gravity, parity and performed prenatal diagnosis, maternal age, the diagnosis of gestational age, prognosis grades, co-existence of extracardiac abnormalities, presence of pathogenic genetic abnormalities, and receiving MDT consultation and management were still independent influencing factors of termination of pregnancy of fetuses with cardiac defects (all P<0.05). A total of 29 (7.2%, 29/400) fetal cardiac defects received MDT consultation and management, and compared with those without MDT management, the pregnancy termination rate in the multiple cardiac defects without extracardiac abnormalities group [74.2%(66/89) vs 4/11] and the multiple cardiac defects with extracardiac abnormalities group [87.9%(51/58) vs 1/5] were lower, the differences were statistically significant respectively (all P<0.05). Conclusions: Maternal age, diagnosed gestational age, severity of cardiac defects, extracardiac abnormalities, pathogenic genetic abnormalities and MDT counseling and management are the influencing factors of fetal heart defects pregnancy decision. MDT cooperation approach influences pregnancy decision-making and should be recommended for the management of fetal cardiac defect to reduce unnecessary termination of pregnancy and improve pregnancy outcomes.
Pregnancy ; Female ; Humans ; Retrospective Studies ; Fetal Diseases/diagnosis* ; Heart Defects, Congenital/therapy* ; Fetus ; Decision Making ; Ultrasonography, Prenatal/methods*

Objective: To analyze the ultrasonic manifestations, clinical features, high risk factors and key points of pregnancy management in prenatal diagnosis of umbilical artery thrombosis (UAT). Methods: The data of 31 pregnant women of UAT diagnosed by prenatal ultrasonography and confirmed after birth from July 2017 to July 2022 at the Women's Hospital, Zhejiang University School of Medicine were retrospectively analyzed, including the maternal characteristics, pregnancy outcomes and fetal complications. In addition, the baseline data and pregnancy outcomes were compared in 21 patients who continued pregnancy after diagnosis of UAT. Of the 21 UAT cases that continued pregnancy, 10 cases were treated with low molecular weight heparin (LMWH; LMWH treatment group), while the other 11 patients had expectant treatment(expectant treatment group). Results: The age of the 31 pregnant women was (30.2±4.7) years, of which 5 cases (16%,5/31) were advanced age pregnant women. The gestational age at diagnosis was (32.9±4.0) weeks, and the gestational age at termination of pregnancy was (35.6±2.9) weeks. In 31 fetuses with UAT, 15 cases (48%) had fetal distress, 11 cases (35%) had fetal growth restriction, and 3 cases (10%) had intrauterine stillbirth. There were 28 cases of live births, including 26 cases by cesarean section and 2 cases by vaginal delivery. There were also 3 stillbirths, all delivered vaginally. Four neonates had mild asphyxia and two newborns had severe asphyxia. Among the 31 cases, 10 cases were terminated immediately after diagnosis, the gestational age at diagnosis was (35.9±2.9) weeks. Another 21 pregnancies continued, and their gestational age at diagnosis was (31.4±3.7) weeks. The median prolonged gestational age in LMWH treatment group was 7.9 weeks (4.6-9.4 weeks), and all were live births. The median prolonged gestational age in the expectant treatment group was 0.6 weeks (0.0-1.0 weeks), and 2 cases were stillbirths. There was a statistically significant difference in prolonged gestational age (P=0.002). Conclusions: Ultrasound is the preferred method for prenatal detection of UAT. Clinicians need to be vigilant for UAT when a newly identified single umbilical artery is detected by ultrasound in the second or third trimesters. The decision to continue or terminate the pregnancy depends on the gestational age and the condition of fetus. Attention should be paid to fetal movements as the pregnancy continues. The treatment of LMWH as soon as possible after diagnosis of UAT may improve the pregnancy outcome.
Pregnancy ; Infant, Newborn ; Female ; Humans ; Adult ; Infant ; Stillbirth ; Cesarean Section ; Umbilical Arteries/diagnostic imaging* ; Asphyxia ; Retrospective Studies ; Heparin, Low-Molecular-Weight/therapeutic use* ; Pregnancy Outcome ; Fetal Growth Retardation/therapy* ; Ultrasonography, Prenatal/methods* ; Gestational Age

OBJECTIVE: To assess the value of chromosomal microarray analysis (CMA) for the diagnosis of fetuses with anomalies of the central nervous system (CNS) and summarize the outcome of the pregnancies and follow-up. METHODS: A total of 636 fetuses from June 2014 to December 2020 who were referred to the Prenatal Diagnosis Center of Nanjing Drum Tower Hospital due to abnormal CNS prompted by ultrasound were selected as the research subjects. Based on the ultrasound findings, the fetuses were divided into ventricular dilatation group (n = 441), choroid plexus cyst group (n = 41), enlarged posterior fossa group (n = 42), holoprosencephaly group (n = 15), corpus callosum hypoplasia group (n = 22), and other anomaly group (n = 75). Meanwhile, they were also divided into isolated (n = 504) and non-isolated (n = 132) groups based on the presence of additional abnormalities. Prenatal samples (amniotic fluid/chorionic villi/umbilical cord blood) or abortus tissue were collected for the extraction of genomic DNA and CMA assay. Outcome of the pregnancies and postnatal follow-up were summarized and subjected to statistical analysis. RESULTS: In total 636 fetuses with CNS anomalies (including 89 abortus tissues) were included, and 547 cases were followed up. The overall detection rate of CMA was 11.48% (73/636). The detection rates for the holoprosencephaly group, ACC group, choroid plexus cyst group, enlarged posterior fossa group, ventricular dilatation group and other anomaly group were 80% (12/15), 31.82% (7/22), 19.51% (8/41), 14.29% (6/42), 7.48% (33/441) and 9.33% (7/75), respectively. Compared with the isolated CNS anomaly group, the detection rate for the non-isolated CNS anomaly group was significantly higher (6.35% vs. 31.06%) (32/504 vs. 41/132) (χ² = 62.867, P < 0.001). Follow up showed that, for 52 fetuses with abnormal CMA results, 51 couples have opted induced labor, whilst 1 was delivered at full term with normal growth and development. Of the 434 fetuses with normal CMA results, 377 were delivered at full term (6 had developmental delay), and 57 couples had opted induced labor. The rate of adverse pregnancy outcome for non-isolated CNS abnormal fetuses was significantly higher than that of isolated CNS abnormal fetuses (26.56% vs. 10.54%) (17/64 vs. 39/370) (χ² = 12.463, P < 0.001). CONCLUSION Fetuses with CNS anomaly should be tested with CMA to determine the genetic cause. Most fetuses with negative CMA result have a good prognosis, but there is still a possibility for a abnormal neurological phenotype. Fetuses with CNS abnormalities in conjunct with other structural abnormalities are at increased risk for adverse pregnancy outcomes.
Female ; Pregnancy ; Humans ; Holoprosencephaly ; Prenatal Diagnosis/methods* ; Central Nervous System ; Fetus/abnormalities* ; Nervous System Malformations/genetics* ; Microarray Analysis ; Central Nervous System Diseases ; Cysts ; Chromosome Aberrations ; Ultrasonography, Prenatal/methods*