RESUMEN
@#Introduction: Estimation of gestational age (GA) is clinically crucial for managing pregnancy and assessing the foetal anatomy, growth and development. Transverse cerebellar diameter (TCD) has been reported as an accurate tool for dating the pregnancy. This study aimed to determine the accuracy of foetal TCD for dating the pregnancy and to construct a reference chart for GA of Yemeni foetuses. Methods: We conducted this prospective cross-sectional study among 400 Yemeni pregnant women between 18 and 40 weeks of gestation provided that they were with known last menstrual period and singleton normal pregnancies. Sonographic TCDs were measured for each foetus. The mean TCD was measured for gestational weeks separately, and a polynomial regression model was then used to predict the GA by TCD. Results: There was a robust correlation between GA and TCD (r = 0.995, p <0.001). The coefficient of determination was 0.989, which indicates that the TCD explains 98.9% of GA change. Conclusion: TCD is an accurate tool to estimate the GA in second and third trimesters, including final weeks, among Yemeni pregnant women as in developed countries. The narrow range between the 5% and 95% percentiles is a significant indication of the accuracy of the TCD in estimating the GA. Therefore, clinicians are recommended to use TCD for estimating the GA and should be trained on measuring it accurately.