Objective: This research aimed to determine the efficacy of Bi ultrasound in estimating the Gestational Age (GA) compared to GA by Nae menstrual period (LMP) date.

Materials and Methods: This was a prospective observational study of w spontaneously conceived viable singleton pregnancy, a regular menstrual cy onset of labor at term. The LMP was considered certain in all cases. We used u fetuses (894 healthy women) and we had 1586Bi-Parietal Diameter (BPD) me collected prospectively and used for statistical analysis. We used Descriptive S an, Standard Deviation (SD), Median and Percentiles values (3rd, 5th, 10th 97th) for BPD measurements on gestational age. We found a regression equat using BPD measurements. The results of the current study were compared with the Paired Differences (t-test analysis). The results were represented as tables & Results: The best-fit equation for the estimate of GA from BPD (in mm) wa