Correlation of Gestational Age Sonographically Using Western Nomogram with That from Last Menstrual Period among North Bengal Population: An Overestimate or Underestimate

Abstract

Context: Pregnant women in India are often unable to recall the last menstruation period (LMP) and also present in the late trimester. In India, to determine the fetal age by ultrasonography (USG), Western nomogram is being used, but the racial and ethnic variation might lead to variation in estimation of fetal parameter. Aim: The aim of this study was to estimate the value of different fetal biometric parameters by USG and to compare it with Western nomogram like Hadlock’s. Settings and Design: This was a descriptive cross-sectional study. Subjects and Methods: The study was performed among 150 pregnant women in their second or third trimester following the inclusion and exclusion criteria. Statistical Analysis Used: The data were analyzed with Microsoft Excel and SPSS (Statistical Package for the Social Sciences) version 22.0. Results: 51.33% of participants were in 29–37 weeks of pregnancy. A statistically significant high positive linear correlation within the estimates of different sonological parameters was found. The observed coefficient of correlation for different parameters was as follows: biparietal diameter (r = 0.968), head circumference (r = 0.963), abdominal circumference (r = 0.964), and femur length (r = 0.963). In the same gestational age (GA), Hadlock’s chart reported higher diameter(s)/length, and differences were noted to be statistically significant. GA estimated by Hadlock’s chart was found to be significantly lower than that of the GA determined from LMP. Conclusion: The biometric sonological fetal parameters in the present study were significantly different from the Hadlock’s chart which notes a considerably higher reading for the same GA, indicating that the probability of race, ethnicity, and sample size played a role.