FETAL HEAD ANTHROPOMETRY: A CROSSSECTIONAL STUDY FROM KUMAUN REGION

Abstract

Introduction: Biparietal diameter (BPD) and head circumference (HC) are important for estimating gestational age (GA), monitoring fetal growth and to rule out congenital abnormalities. Western references using HC and BPD can lead to erroneous GA estimation, therefore regional reference is required. Aim: To measure HC and BPD in fetus at different GA, their relationship with GA and comparison of HC and BPD with expected HC and BPD by “Hadlock’s formula”. Material & Methods: CRL, HC and BPD were measured in 72 fetuses. Mean and standard deviation of HC and BPD were calculated for all fetuses and across three trimesters. The correlation of HC and BPD with GA was calculated and p value was derived. Hadlock’s HC and BPD were calculated for the gestational age. The observed HC and BPD in the study were compared with the Hadlock’s value to find out any difference between them Results: The mean HC of fetuses was 23.7 ± 8.58 cm. The mean HC in first trimester was 6.3 cm, 15.13 cm in second trimester and 30.8 cm in third trimester. The mean HC of fetuses according to Hadlock’s formula was 23.72 ± 8.80 cm. The mean Hadlock’s HC in first trimester was 5.6 cm, 14.92 cm in second trimester and 31.12 cm in third trimester. The mean BPD in the studied fetuses was 5.92 ± 2.24 cm. The mean BPD in first trimester was 1.7 cm, 4.8 cm in second trimester and 7.8 cm in third trimester. The mean Hadlock’s BPD was 6.33 ± 2.41 cm. The mean Hadlock’s BPD in first trimester was 1.6 cm, 4.4 cm in second trimester and 8.3 cm in third trimester. The mean HC of fetuses were nearly equal to mean Hadlock’s formula, while BPD of the study fetuses was less than mean Hadlock’s BPD. Both HC and BPD measured at different GA showed increase, with increase in GA and strong positive correlation and statistically significant association. Conclusion: This study had shown that while HC is nearly equal to Hadlock’s reference, BPD was less than Hadlock’s for GA, reflecting need of local reference data for accurate fetal age estimation.