Nuchal translucency (NT) is the sonographic appearance of the subcutaneous accumulation of fluid behind the fetal neck in the first trimester of pregnancy. NT is measured between 11 to 13 weeks gestation with the optimal measurement of crown-rump (the length of an embryo or fetus measured from the skull vertex to the midpoint between the apices of the buttocks10) of 45 mm to 84 mm. Most fetuses can be viewed transabdominally scan, while some need additional transvaginal examination2. The image of measuring the NT should be obtained with mid-sagittal plan including fetal’s head and upper thorax only1, 2. Furthermore, hyperextension position of fetal’s neck can increase NT measurement by 0.6 mm and in flexion, the measurement decrease by
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Down syndrome is the most common abnormal genetic defect associated with increased NT thickness2. The nuchal fold’s components, and extent, are not considered in the word ‘translucency’ of the scan’s name “Nuchal Translucency”; the occurrence of genetic defects and the prognosis cannot be expected by the appearance of the lesion1. So, in normal and abnormal pregnancies, the NT can be found and it is not a pathological condition2. Normal fetuses with increased NT thickness usually recover after 14 weeks of gestation4. In some cases NT develops into generalize hydrops or enlarged nuchal fold4. The degeneration of nuchal translucency could occur after the 13th week of gestation and the development changes, which include cystic hygromas and nuchal edema, could happen in the 14th - 22nd weeks of gestation1. Due to modification nature of NT, scan should be between 11 week and 13 week of …show more content…
Concerning the ability of mothers to do NT screening, Karnmen et al, mentioned that ultrasound screening requires all pregnant women to go to appropriate health care centers with a great equipment quality within a limited time (11 – 13 weeks of gestation), in addition, they mentioned that NT screening should be introduced as a separate entity and not just during a first trimester scan for other reasons, moreover, Karnman thought that his study’s results were not promising as Nicolaides et al. or Pandya et al and he declared regardless of high-resolution equipment and experienced sonographers, NT measurement was successful in only 58% of all cases; 45% < 10 weeks and 74% > 10 < 13 weeks of gestation, which lead to rebooking of 42% of first trimester scans, leading to marked increase in work-load and extra ultrasound exposure to the fetus13. In matter of the cost-effectiveness of NT screening, Caughey assumed if NT screening was adopted as a universal screening modality, it will determine the possible impact of it, however, if the NT screening was combined with quality-adjusted life year measurement (QALY) and alpha-fetoprotien test
Down syndrome is the most common abnormal genetic defect associated with increased NT thickness2. The nuchal fold’s components, and extent, are not considered in the word ‘translucency’ of the scan’s name “Nuchal Translucency”; the occurrence of genetic defects and the prognosis cannot be expected by the appearance of the lesion1. So, in normal and abnormal pregnancies, the NT can be found and it is not a pathological condition2. Normal fetuses with increased NT thickness usually recover after 14 weeks of gestation4. In some cases NT develops into generalize hydrops or enlarged nuchal fold4. The degeneration of nuchal translucency could occur after the 13th week of gestation and the development changes, which include cystic hygromas and nuchal edema, could happen in the 14th - 22nd weeks of gestation1. Due to modification nature of NT, scan should be between 11 week and 13 week of …show more content…
Concerning the ability of mothers to do NT screening, Karnmen et al, mentioned that ultrasound screening requires all pregnant women to go to appropriate health care centers with a great equipment quality within a limited time (11 – 13 weeks of gestation), in addition, they mentioned that NT screening should be introduced as a separate entity and not just during a first trimester scan for other reasons, moreover, Karnman thought that his study’s results were not promising as Nicolaides et al. or Pandya et al and he declared regardless of high-resolution equipment and experienced sonographers, NT measurement was successful in only 58% of all cases; 45% < 10 weeks and 74% > 10 < 13 weeks of gestation, which lead to rebooking of 42% of first trimester scans, leading to marked increase in work-load and extra ultrasound exposure to the fetus13. In matter of the cost-effectiveness of NT screening, Caughey assumed if NT screening was adopted as a universal screening modality, it will determine the possible impact of it, however, if the NT screening was combined with quality-adjusted life year measurement (QALY) and alpha-fetoprotien test