European Journal of Biomedical and Pharmaceutical Sciences

GESTATIONAL AGE DETERMINATION USING FETAL TRANSCEREBELLAR DIAMETER IN THIRD TRIMISTER AND EVALUATION OF TCD/AC RATIO IN THE ASSESSEMENT OF FOETAL GROWTH IN INDIAN POPULATION

Dr. Arun Kumar S.* and Dr. Sangeetha Devi P.S.

ABSTRACT

Aims and Objective 1. To assess the usefulness of fetal transcerebellar diameter as an independent parameter for gestational age assessment in the third trimester of pregnancy. 2. To derive nomogram for estimating the gestational age of the foetus from ultrasonographically measured transverse cerebellar diameter in Indian population. Materials and Methods: Hardware: GE Voluson P8. Methods: Hospital based prostective study. 148 healthy pregnant patient in third trimester were included in the study who underwent obstetric sonography in Department of Radiology, Karpagam Faculty of medical science and research, Coimbatore. Transverse cerebellar diameter is obtained in the axial plane in the cerebellar view i.e with a slight rotation of the transducer approximately 300 from the conventional thalamic plane where the biparietal diameter is measured using the cavum septipellucidi, third ventricle and thalami as landmarks. In this plane posterior fossa with cerebellum is visualized. The cisterna magna is just posterior to the cerebellum. This plane provides the widest transcerebellar diameter. Gestational age for the measured TCD is obtained from the reference chart “Predicted menstrual age for transverse cerebellar diameter of 14 mm to 56 mm”by Hill et.al., in his study “Transverse cerebellar diameter as a predictor of menstrual age” in 1990. TCD/AC ratio was calculated according to the following formula: TCD/AC ratio (%): TCD (mm)/AC (mm) x 100 Conclusion: TCD correlates with clinical gestational age as the first best parameter and also positively correlates with BPD, HC, AC and FL. So TCD can be reliably be used for gestational age assessment in third trimester. TCD/AC ratio remains fairly constant in third trimester with value of 14.59 +/- 2SD, So the ratio is independent of gestational age and can be used in assessing the fetal growth in pregnancies with unknown dating.

Keywords: To assess transcerebellar prostective study.