Background: The exact determination of gestational age is so important in management of outpatient care and for adequate planning of proper intervention or therapy. Transcerebellar diameter has great advantages in prediction of gestational age in cases of uncertain dates or suspected intrauterine growth retardation (IUGR). There are minimal data available about the relationship between transcerebellar diameter and biparital diameter in second trimester of pregnancy.
Objective: To assess the diagnostic accuracy of transcerebellar diameter (TCD) measurement in estimation of the gestational age during the second trimester compared with the other fetal biometric measurements including femur length (FL) and biparital diameter (BPD).
Patients and Methods: This study was carried out on 200 pregnant women with normally progressing pregnancies during the second trimester with gestational age between 16 – 28 weeks. The criteria for inclusion in the study were singleton gestation, head presentation, absence of fetal anomalies, and no history of chronic diseases or abnormal babies or stillbirths. All patients provided informed consents and were subjected for assessment of history, general and abdominal exanimation, and ultrasound (US) to assess: Fetal viability, BPD, FL, AC and TCD. Transabdominal ultrasound (TAUS) was performed for all participants. Fetal TCD was measured by locating the cerebellum in the posterior fossa by means of rotation of the transducer to 30o from the plane that identified the thalamus cavity of the septum pellucidum, third ventricle and cisterna magna (CM), positioning the calipers on the outer margins of the cerebellar hemispheres. at Department of Obstetrics and Gynecology, Al-Hussien and SayedGalalHospitals, Al-AzharUniversity (inpatient and outpatient) from April 2020 to October 2020.
Results: The transcerebellar diameter (TCD) was more accurate than the biparital diameter (BPD). There were significant statistical differences between transcerebellar diameter (TCD) and biparietal diameter (BPD), and between transcerebellar diameter (TCD) and femur length (FL) for determination of gestational age in the second trimester. All those data were compared to the last menstrual period (LMP).
Conclusion: Transcerebellar diameters (TCD) was more reliable method of gestational age (GA) determination in the second trimester of pregnancy than Bi-parietal diameter (BPD). TCD can be used as a tool to assist in the assessment of GA in the second trimester.