Accuracy of Transcerebellar Diameter at the Third Trimester in Estimating the Gestational Age in Singleton Pregnancy

Objective: The aim of the current study was to evaluate the accuracy of fetal transcerebellar diameter (TCD) in estimating the gestational age at the third trimester of pregnancy. Methods: The current diagnostic test accuracy study was conducted at the Special Care Center for the Fetus at Ain Shams University Maternity Hospital during the period between September 2011 and December 2012. The study included singleton pregnant women, during their last trimester (at gestations between 28 and 41 weeks). Transabdominal ultrasonography was performed to all included women for measuring the biparietal diameter (BPD), femur length (FL) and TCD. Results: A total of 150 women were included in the current study. The mean gestational age was 35.17±3.56 weeks (range: 28-41 weeks). Bland-Altman analysis of agreement showed a non-significant difference between gestational age estimated by last menstrual period (LMP)/crown-to-rump length (CRL) and the estimated gestational age using each of TCD and BPD and/or FL, in all included women, and when analysis was split above and below 36 weeks of gestation. Conclusion: TCD seems to be as accurate as BPD and FL in estimating the gestational age in both term and preterm late pregnancy.