Background: First-trimester ultrasound was initially done for confirming pregnancy, counting fetuses, and dating. Later, combined trisomy 21 screening became crucial, Nuchal Translucency (NT), measured at 11-13 weeks + 6 days, indicates chromosomal defects with increased thickness. It's an effective marker for trisomies, triploidy, Turner syndrome, and congenital heart defects. More over, intracranial translucency (IT) assessment is a useful tool for prediction NTDs. 
Aim of study: The aim was to evaluate the diagnostic accuracy of nuchal and intracranial translucency assessment by two-dimensional (2D) versus three-dimensional (3D) ultrasonography in low-risk pregnancy at the first trimester.
Patients and methods: This study was a Cross sectional study conducted at Outpatient clinic at obstetrics and gynecology department at Mansoura University Hospital from May 2021 to May 2022. Study population included 30 Low risk pregnant women with their gestational ages ranging from 11–13 weeks and six days.
Results : there was no statistically significant difference in assessment the NT and IT by 2D ultrasound and 3D ultrasound.  
Conclusion: There was a complete matching between 2D and 3D ultrasound in detection of IT and NT in low-risk pregnancy at the first trimester.