Abstract:
Nuchal translucency (NT) is the fluid collection behind the fetal neck which canbe measured by ultrasound at 11-14 weeks of gestation. Increase in the nuchal translucency thickness is associated with various congenital anomalies. To study the relationship between nuchal translucency thickness, crown rump length and gestational age in normal fetus. MethodProspective analytical study conducted on 50 pregnant women from augest 2015 to october 2015 using trasabdominal ultrasound.. The relationship between nuchal translucency thickness, crown rump length and gestational age was studied by using linear regression analysis. Results of this study showed that the mean CRL was57.86 (range 41.2-88mm) and mean NT thickness was 2.4mm 0.35mm (range 1.1-2.9mm), respectively. The median gestational age was 12.9weeks. The regression equation which shows relation between median NT thicknes and CRL was described as follows: expected NT thickness = 0.01333CRL+1.2389, (R2 =0238, p <0.001). There was increase in the incidence of NT thickness more than or equal to 2.5mm; 1.7% in fetus between 12-12.9 weeks of gestation to 15.1% in fetus between 14.0-14.9 weeks. Our study offers normative data of NT thickness in normal fetus, which can be used as reference to screen various chromosomal and congenital abnormalities between 11-14 weeks of gestation. NT thickness increased with increasing CRL and a false positive rate increases with increasing gestational age.
