Prediction of gestational age by ultrasonogram using linear regression model

Introduction: Estimation of an accurate due date is of both social and medical significance. Care providers are dependent on gestational age to schedule maternal and fetal investigations, to gauge parameters of fetal growth and apply interventions timely for the management of prenatal complications. This study was done to develop a linear regression model using ultrasound measurement of fetal parameters to predict the gestational age in pregnancy. Methodology: This study was carried out as a multicentre cross sectional study in one government and one private tertiary care hospitals in Chennai among 145 antenatal women. Gestational age was determined by measuring fetal parameters like Mean sac diameter, Biparietal diameter, Crown rump length, Abdominal circumference, Head circumference, Femur length and Effective fetal weight. Results: The mean age of the participants was 27.5 years. About 57 % of subjects were between 25-30 years and nearly 23 % of the subjects were in the age group 20-25 years. Overall, 55(37.9%) of the participants were in 3rd trimester. There was a statistically significant correlation between the fetal parameters and gestational age in the second trimester (p<0.001). Conclusion: Fetal parameters are key predictors of gestational age. They are useful to detect fetal abnormalities. It is essential to assess the gestational age using multiple parameter. It is likely that the technological development of USG will continue and increases in ultrasound frequency will further improve image resolution of early pregnancies. A 3D and 4D USG will also improve our ability to assess early pregnancy viability and multiple gestations.