Predictive Value of Fetal Nuchal Translucency in Screening of Chromosomal Aberrations (original) (raw)
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Acta Obstetricia et Gynecologica Scandinavica, 1998
Background. To evaluate the implementation of nuchal translucency measurement as an additional examination within the first trimester routine ultrasound in an unselected population of women. Methods. A prospective study in which all pregnant women during 1994, referred for the first trimester routine ultrasound scan, were asked to participate. Of a total of 1852 women with a viable pregnancy, results from 1444 women were evaluated. When a nuchal translucency of 4 mm or more was found, the woman was offered both a genetic amniocentesis in gestational week 13-15 and an additional ultrasound examination in gestational week 18-19. Results. Six fetuses had a nuchal translucency of 4 mm or more and none of these had any chromosomal abnormality. Neither had any of the fetuses in the study, karyotyped for other reasons, any chromosomal defect and nor was there any child born with aneuploidy in the study population. No strong relation between major malformations e.g. abnormalities of the heart and increased nuchal translucency was found. The fetus with the largest nuchal translucency (Ω6 mm) was born healthy. Conclusion. The efficacy of nuchal translucency measurement needs further evaluation before it can be introduced as a screening method in an unselected pregnant population.
Ultrasound in Obstetrics and Gynecology, 2009
K E Y W O R D S: first trimester; nuchal translucency; quality assurance; screening; trisomy 21 ABSTRACT Objectives To examine the effect of deviations in median nuchal translucency thickness (NT) and the spread in measurements on the performance of screening for trisomy 21 by maternal age and fetal NT, and by maternal age, fetal NT and maternal serum biochemistry.
Ultrasound Markers of Chromosomal Anomalies in the First Trimester
Donald School Journal of Ultrasound in Obstetrics & Gynecology, 2009
Chromosomal anomalies are associated with considerable morbidity and mortality. The protocol for identifying these fetuses had for many years included a single clinical criterion of maternal age. Advances in biochemical screening combined with the excellent display of fetal dysmorphology afforded by technological advances in ultrasound equipment have resulted in a paradigm shift in the diagnosis of chromosomal abnormalities in the fetus, from the second trimester to the late first trimester. The accuracy of diagnosis as reported in multiple large series has pushed both screening and diagnostic testing for chromosomal disorders to the window now referred to as the 11 to 13 weeks + 6 days scan. Recent data have shown chorion villus sampling after 10 weeks to be as safe in experienced hands as amniocentesis and this has pushed the advantages of first trimester screening further. Ultrasound parameters for the detection of Down's syndrome in the first trimester include the nuchal translucency (NT) as the most well-defined and studied parameter, evaluation of the nasal bone (NB), frontomaxillary facial (FMF) angle, ductus venosus (DV) flow velocity waveform, tricuspid regurgitation (TR) and fetal heart-rate. Each parameter has well-defined criteria to be fulfilled for accurate quantification. Biochemical parameters that are currently in wide use include PAPP-A and free beta-hCG. Other parameters that the software accounts for are the gestational age assessed by the crown-rump length, maternal age, ethnicity, smoking, IVF and number of fetuses with chorionicity. Combining maternal age, biochemistry, NT and NB between 11 to 13 weeks + 6 days yields a detection rate of 96% with a false positive rate of 5%.
2012
Ankara, Turkey OBJECTIVE: We sought to determine the value of well defined screening method in predicting trisomy cases in our institution. STUDY DESIGN: Totally 300 amniocentesis cases were screened from prospectively collected database. Subjects were referred to amniocentesis according to the sequential results of first and second trimester screening tests. Each case had nuchal translucency measurement between 11 th to 14 th weeks of gestation. All values of NT measurement were analyzed to predict trisomy cases. RESUlTS:There were 7 trisomy cases , non of the screening methods significantly predicted trisomy cases (p>0.05) rather than the simply age (Area under curve 0.724, p=0.043). Mean NT did not differ between groups with normal and abnormal chromosomes(p>0.05). CONClUSION: This data led us to conclude that in our country there is still need for more accurate and standardized method to predict abnormal cases with higher sensitivity and specificiy to decrease invasive procedures.
Analysis of quality of nuchal translucency measurements: its role in prenatal diagnosis
2012
Objective. Quantitative analysis of the quality of nuchal translucency (NT) measurements. Methods. First-trimester combined screening for Down syndrome was performed to all pregnant women attended in our Department from October 2003 to November 2009. NT was measured according to the Fetal Medicine Foundation (FMF) criteria by 20 trained obstetricians. The performance of NT measurements was retrospectively analyzed with regard to several quality control standards. Accuracy according to experience, professional profile, crown rump length (CRL) values, and FMF certification was statistically tested. Results. A total of 14978 NT measurements were assessed. (1) The mean operator-specific median NT-MoM values was 0,98. (2) Mean percentage of cases >95th and <5th centiles were 5,0% and 4,2%, respectively. (3) Logarithmic mean and SD of the NT MoM values were 0,00 and 0,13, respectively. (4) The DR for trisomy 21 at screening time was 90,7% for a FPR of 6,7% for standard screening strategy. (5) According to Cumulative SUM (CUSUM) figures, the performance was more acceptable in FMF-certified operators. Conclusion. Overall, quality standards show optimal NT measurements in our unit. Operator experience, a dedicated profile to fetal medicine, CRL over 60 mm, and FMF certification have a significant positive impact on the quality standards.
Increased nuchal translucency thickness and normal karyotype: time for parental reassurance
Ultrasound in Obstetrics and Gynecology, 2007
To study the outcome of pregnancy in chromosomally normal fetuses with increased nuchal translucency thickness (NT), with respect to fetal loss, structural defects and genetic syndromes with developmental delay, and to provide information that would be helpful for parental counseling on the residual risk of adverse outcome when ultrasound findings are normal.
Ultrasound in Obstetrics & Gynecology, 2011
Objective Fetal nuchal translucency (NT) is assessed by ultrasonography as a screening tool for aneuploidy at 11 to 13 + 6 weeks' gestation. Fetuses with increased NT but apparently normal karyotype are still at higher risk of structural abnormality and a range of genetic syndromes, which may be related to major and submicroscopic chromosomal abnormalities. The aim of this study was to report the prevalence of submicroscopic chromosomal abnormalities in a cohort of apparently euploid fetuses that presented with increased NT.