No abstract available.
Fetus* ; Nuchal Translucency Measurement* ; Pregnancy*

No abstract available.
Female ; Humans ; Nuchal Translucency Measurement* ; Pregnancy Trimester, First* ; Pregnancy*

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.

OBJECTIVE: To evaluate the efficiency of the measurement of fetal nuchal translucency (FNT) and ductus venosus Doppler examination (DV Doppler) as a screening tool for chromosomal abnormalities. METHODS: FNT measurement and DV Doppler wereperformed in 950 pregnancies between 11(+0)~13(+6) weeks' gestation. Chromosomal analysis was done when FNT was more than 3 mm and DV Doppler showed absent flow or reversed flow. The numbers of cases with increased FNT and abnormal DV Doppler were counted in the groups of abnormal and normal karyotype. RESULTS: Data were available in 912 pregnancies. 11 pregnancies showed abnormal karyotype (1.2%). In the 11 cases with abnormal karyotype,increased FNT was found in 8 cases with 72.7% sensitivity and abnormal DV Doppler was found in 5 cases with 45.4% sensitivity. In the 901 cases withnormal karyotype, increased FNT was found in 33 cases with 96.3% specificity and abnormal DV Doppler was found in 12 cases with 98.7% specificity. Positive predictive value was 19.5% in cases of increased FNT, 29.4% in cases of abnormal DV Doppler, and 44.4% in cases of increased FNT and abnormal DV Doppler both. CONCLUSION: There is no improvement in general screening for chromosomal abnormalities when FNT measurement and DV Doppler were performed together. But better specificity and positive predictive value for chromosomal abnormalities were found.
Abnormal Karyotype ; Chromosome Aberrations ; Karyotype ; Mass Screening ; Nuchal Translucency Measurement ; Pregnancy ; Sensitivity and Specificity

OBJECTIVE: To examine a normal range for nuchal translucency thickness between 9 and 14 weeks' gestation in normal fetuses. METHODS: Nuchal translucency was measured prospectively in 124 fetuses between 9 and 14 weeks' gestation resulted in normal pregnancy outcome. The nuchal translucency measurement was expressed as the median and the 5th, 25th, 75th, and 95th percentiles according to complete weeks of gestation based on ultrasound measurement. RESULTS: The median nuchal translucency thickness was 1.8 mm at 9 weeks' gestation and it declined to 1.6 mm at 10 weeks. But the median thickness increased from 1.95 mm at 11 weeks to 2.3 mm at 12 weeks, after which it slightly declined to 2.25 mm at 13 weeks. And then it increased to 2.5 mm at 14 weeks. A nuchal translucency thickness greater than 2.5 mm was not found at 9 and 10 weeks' gestation, but found in 21.8% of fetuses from 11 weeks to 14 weeks. CONCLUSION: In normal fetuses, there is a physiologic variation in the thickness of nuchal translucency between 9 and 14 weeks' gestation. The calculation of risk for trisomies based on this thickness should take this variation into account. The adoption of a gestational age-dependent cutoff point, based on the deviation of a given measurement from the median, may reduce the invasive procedure for karyotyping. And this study suggest that if the nuchal translucency measurement is greater than 2.5 mm before 10 weeks, it may advise the karyotyping.
Female ; Fetus* ; Karyotyping ; Nuchal Translucency Measurement* ; Pregnancy ; Pregnancy Outcome ; Prospective Studies ; Reference Values ; Trisomy ; Ultrasonography

Nuchal translucency is an important indicator of an aneuploid fetus in prenatal diagnostics. Previously, only the presence of aneuploid could be confirmed by conventional karyotyping of fetuses with thick nuchal translucency. With the development of genetic diagnostic techniques, however, it has been reported that subtle variations not detectable by conventional karyotyping might occur in cases of pathologic clinical syndrome in euploid fetuses. One of the newer, high-resolution genetic methods in the prenatal setting is chromosomal microarray. The possible association between nuchal translucency thickness with normal karyotype and submicroscopic chromosomal abnormalities detectable by microarray has been studied. How and when to apply microarray in clinical practice, however, is still debated. This article reviews the current studies on the clinical application of microarray in cases of increased nuchal translucency with normal karyotype for prenatal diagnosis.
Aneuploidy ; Chromosome Aberrations ; Comparative Genomic Hybridization ; Fetus* ; Karyotype ; Karyotyping ; Microarray Analysis* ; Nuchal Translucency Measurement* ; Prenatal Diagnosis

OBJECTIVE: To explore the correlation between fetal nuchal fold (NF) thickening and fetal chromosomal abnormality. METHODS: In total 919 pregnant women undergoing ultrasound examination were selected for interventional prenatal diagnosis in order to detect fetal chromosomal abnormality. RESULTS: The detection rate of chromosomal abnormality has significantly increased with NF thickness, advanced maternal age, presence of other ultrasound abnormalities (P<0.05). Trisomy 21 was the most common abnormality, and there was a prepondance for male fetuses. CONCLUSION Increased NF thickness is strongly associated with the risk of fetal chromosomal abnormalities, advanced maternal age and presence of additional ultrasound abnormalities.
Chromosome Aberrations ; Female ; Fetus ; Humans ; Maternal Age ; Nuchal Translucency Measurement ; Pregnancy ; Ultrasonography, Prenatal

Prenatal diagnosis of Down syndrome requires an invasive test in women considered to be at high risk after screening. At present, there are variable screening tests. For a 5% false-positive rate, the sensitivities are approximately 20-30% for maternal age alone, 60-70% for maternal age and second-trimester maternal serum markers, 85% for maternal age with fetal nuchal translucency and maternal serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11-14 weeks, and 94% for maternal age with fetal nuchal translucency and maternal serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11-14 weeks following second-trimester maternal serum markers. This article examines the studies of screening for Down syndrome and summarizes the results from major studies reporting on the implementation of this method.
Biomarkers ; Chorionic Gonadotropin ; Down Syndrome* ; Female ; Humans ; Mass Screening ; Maternal Age ; Nuchal Translucency Measurement ; Pregnancy-Associated Plasma Protein-A ; Prenatal Diagnosis*

The present report describes a case that showed a normal fetal karyotype in an antenatal genetic study but an abnormal placental karyotype of 46,XX,r(15) on postnatal examination. The pregnancy was complicated by fetal nuchal translucency in the first trimester and intrauterine growth restriction in the second and third trimesters. A 1780 gm female baby was born after 40 weeks of gestation, but died of respiratory distress and sepsis on the 10th day of life. Our case was unique in that the placental chromosomal aberration was a structural abnormality instead of a numerical aberration that is seen in most reported cases of confined placental mosaicism.
Chromosome Aberrations ; Female ; Humans ; Karyotype ; Mosaicism* ; Nuchal Translucency Measurement ; Pregnancy ; Pregnancy Trimester, First ; Pregnancy Trimester, Third ; Sepsis

A first-trimester ultrasound scan has become an essential part of antenatal care. The Korean Society of Ultrasound in Obstetrics and Gynecology held a first-trimester ultrasound forum on April 5, 2014. The forum aimed to present an updated review of the literature on the topic of first-trimester ultrasound in specific lectures and to host a panel discussion on several important issues regarding first-trimester scans. The forum provided evidence- and consensus-based best practice patterns for obstetricians in Korea. Here, we report the review and checklists presented from the forum.
Checklist ; Female ; Gynecology* ; Humans ; Korea ; Lectures ; Nuchal Translucency Measurement ; Obstetrics* ; Practice Guidelines as Topic ; Pregnancy ; Pregnancy Trimester, First ; Ultrasonography*