Evaluation of Fetal Transcerebellar Diameter as a Sonological Parameter for the Estimation of Fetal Gestational Age in Comparison to Biparietal Diameter and Femur Length

ABSTRACT

Background: Knowledge of the expected date of delivery is essential in the management of all pregnancies, particularly those which require active management. Presently the most effective way to date the pregnancy is by the use of ultrasound. Several sonographically derived fetal parameters are used to date pregnancies, those include Biparietal diameter (BPD), Head circumference (HC), Abdominal circumference (AC) and femur length (FL). However, the variability of these parameters increases with increasing age. Transverse cerebellar diameter (TCD) measurement can be used as a new parameter to estimate the fetal gestational age. The present study was undertaken to evaluate the usefulness of Trans cerebellar diameter (TCD) as against other conventional parameters (like Biparietal diameter and Femur length) in normal pregnancies. Objectives: To evaluate the usefulness of Trans cerebellar diameter (TCD) as against the conventional parameters of Biparietal diameter (BPD) and Femur length (FL) in normal pregnant mothers between 15-37 weeks, to derive nomogram for estimating the gestational age of the fetus from measured transverse cerebellar diameter. Sumanta Kumar Mandal, Sandip Kumar Ghosh, Saikat Roy, Barun Prakash. Evaluation of Fetal Transcerebellar Diameter as a Sonological Parameter for the Estimation of Fetal Gestational Age in Comparison to Biparietal Diameter and Femur Length. IAIM, 2019; 6(6) 41-50. Page 42 Materials and methods: Study of 100 normal pregnant women between 15-37 weeks of gestation. For each patient BPD, FL and TCD were measured. From the above measured parameters gestational age was measured using Hadlock tables. TCD was compared with BPD, FL in normal pregnancies. Results: It was observed that there was a statistically significant curvilinear relationship between TCD and gestational age in normal pregnancies. The growth pattern of cerebellum followed a second degree polynomial similar to that of BPD and FL. Gestational age estimated by TCD correlated well with the estimated gestational age by BPD and FL. Conclusion: Transverse cerebellar diameter (TCD) shows good correlation with gestational age and can be used as a single growth parameter to estimate the gestational age where LMP is uncertain.