Determination of the Accuracy of Transcerebellar Diameter in Estimating Gestational Age in the Second and Third Trimesters of Pregnancy.

Background Every antenatal woman and her treating doctor aim for a healthy newborn. In obstetrics, accurately determining the gestational age (GA) is a critical aspect of managing pregnancy and evaluating fetal growth and development. The transcerebellar diameter (TCD) is the greatest transverse measurement of the fetal cerebellum. The growth of the cerebellum is minimally affected by fluctuations in growth, making the TCD the most reliable measurement for predicting GA. The purpose of the present research is to determine the accuracy of TCD in estimating GA in the second and third trimesters of pregnancy. Materials and methods The study included 500 antenatal women at 18-40 weeks of gestation. We also measured TCD in addition to routine ultrasound parameters like biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL). We used IBM SPSS Statistics for Windows, Version 22 (Released 2013; IBM Corp., Armonk, New York, United States) for statistical analysis. The collected data was subjected to statistical tests, including Pearson's correlation coefficient and coefficient of determination. We conducted a regression analysis and used correlation coefficients to compare each ultrasound-measured parameter with the GA. Results The current research demonstrates a significant linear relationship between the TCD and GA (r = 0.9865; p = 0.0001), a strong association between BPD and GA (r = 0.9541; p = 0.0001), between HC and GA (r = 0.9613; p = 0.0001), between AC and GA (r = 0.9489; p = 0.0001), and between FL and GA (r = 0.9697; p = 0.0001). TCD showed the best correlation with GA among all the biometric parameters. TCD showed a correct assessment of GA by the last menstrual period (LMP) in 479 (95.8%) antenatal women. Conclusion The current research concludes that the TCD can be utilized as an independent measure to determine GA in the second and third trimesters of pregnancy, particularly in cases where the LMP is unknown, no dating scan has been performed in the first trimester, initial assessment taking place in the third trimester and in fetuses with variations in head shape such as dolichocephaly and brachycephaly.