Objective: The aim of this study is to determine the normal pattern of growth of various fetal orbital parameters (BOD, OD & IOD) and their correlation with gestational age in the local population.

Materials and Methodology: A cross-sectional study was conducted at University of Lahore Teaching Hospital, during the period from January 2020 till July 2020 on 300 pregnant females in the second and third trimester of pregnancy.

Results: Using linear regression analysis with gestational age as an independent variable, a strong linear relationship was found between gestational age and fetal orbital parameters including BOD, OD and IOD with R²=0.891, R²=0.829 and R²=0.714. It was generally more strong with BOD in comparison with the rest of orbital biometric measurements.  Study also showed significant correlation between fetal orbital biometric parameters (BOD, OD & IOD in mm) with gestational age with correlation coefficient r = 0.944, 0.911 and 0.845 respectively with all showing p value of <0.001.

Conclusion: Fetal orbital parameters including BOD, IOD and OD have also found their usefulness in assessing gestational age of fetus especially in cases where the patient is unsure of dates or on clinical examination fundal height does not correspond with gestational age. Routine evaluation of orbital parameters during obstetrical scans can help in diagnosing ocular/orbital pathologies at any early gestation.

Keywords: Binocular distance, Interocular distance, Orbital diamtere.