Objective: The aim of this study was to compare the fetal biometric growth measurements (Head Circumference, Bi-Parietal Diameter, and Femur Length) between male and female fetuses on antenatal ultrasound in our population.

Methodology: This was an observational study carried out in the Department of Radiology CMH Malir, Karachi and Ziauddin hospital, Karachi from July 2016 till July 2018 using non-probability sampling technique. A total of 510 pregnant women with second and third trimester were enrolled for the study. The biometric parameters of fetus i.e., Bi-Parietal Diameter, Head Circumference, and Femur Length were established through two-dimensional ultrasound. Chi-square and t tests were used to analyze differences in biometric parameters in both genders.

Results: The study results showed significant differences in the Bi-Parietal Diameter and Head Circumference between male and female fetuses (p=0.006 and p=0.003, respectively). Mean Bi-Parietal Diameter in males was 71.47±13.70 and in females it was68.30±11.90cm, mean Head Circumference in males was 264.23±47.87and in females it was 252.03±44.91cm. It has also been observed that there was an insignificant difference in the femur length between male and female fetuses (p= 0.605). Mean femur length was 52.74±12.39 in males and 52.19±11.38 in females. Conclusion: This study concluded that male fetuses have considerably larger bi-parietal diameter and head circumference as compared to female fetuses however, no variation in femur length is observed in both genders. Keywords: Fetal Gender, Bi-Parietal Diameter, Head Circumference, Femur Length