Determining the Role of Nuchal Translucency for Detection of Chromosomal Aberration in Vietnam

The present study investigate the sensitivity and specificity of various nuchal translucency thresholds in the identification of chromosomal abnormalities. This study is the first study to compare the sensitivities of nuchal translucency alone as a screening test for chromosomal aberration with different cut-offs in a Vietnam population. This is a longitudinal study of pregnant women have first trimester screening and ultrasound in center of diagnostic antenatal of national hospital of obstetrics and gynecology. The threshold 2.5mm for increased fetal nuchal translucency had sensitivity- specificity average of 87.25 % and OR = 242.799(95%CI: 60.004-982.465) in diagnosis of chromosomal defects. It had sensitivity- specificity average of 86.85 % in diagnosis of Down syndrome. It had sensitivity- specificity average of 87.75 % in diagnosis of sex chromosomal defects. It had sensitivity- specificity average of 85.95% in diagnosis of other chromosomal aneuploidies. It had sensitivity- specificity average of 84.3% with OR= 62.424 (95% CI: 15.583-768.096) in diagnosis of structural rearrangement of chromosomes. In Vietnam, fetuses with increased nuchal translucency, more than a half of the chromosomally abnormal group is affected by defects other than trisomy 21 (52.2%). The threshold for chromosomal defects diagnosis is highest at 2.5mm cutoff point with the average of sensitivity and specificity is 87.25%.