Determination of The Mean Fetal Biometrics and The Mean of Ratio of biometrics in 2nd and 3rd Trimester of Pregnancy in Correlation with Fetal Gestational Age: As a Predictive Biometric Parameters

Abstract

Introduction: Fetal cerebellar diameter in normal gestation is also highly correlated with fetal growth indices. Objective: To determine to mean fetal biometric ratios in 2nd and 3rd trimester of pregnancy on ultrasound as a predictive biometric parameter of gestational age. Study Design: Cross-sectional study. Material and Methods: A total of 140 pregnant women in their second and third trimester were included in this study. BPD, AC, FL and TCD were measured on ultrasound, by identifying the cerebellum in the posterior cranial fossa and measuring it in from outer edge to outer edge. Results: Mean age of the patients was 25.80±4.11 years. Mean gestational age was 28.8±7.45 weeks. In the present study, mean TCD was 32.33±11.61 cm. After applying the regression test gestational age with TCD (mm) had significant relation (r=0.922 p<0.001). Similar relation also found with BPD, AC and FOD. But the ratio of BPD/AC, TCD/AC were remaining static through pregnancy. Conclusion: In the normally developing fetus, not only TCD/AC is constant but also BPD/AC and FOD/AC have remained gestational age independent.

Keywords: Gestational age, transcerebellar diameter, third trimester of pregnancy