ULTRASONOGRAPHIC ASSESSMENT OF FOETAL LEG BONE LENGTHS FOR ESTIMATION OF GESTATIONAL AGE
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Keywords
Gestational age; Ultrasonography; Foetal femur; Tibial length; Foetal biometry
Abstract
Accurate estimation of gestational age (GA) is essential for optimal antenatal care, timely obstetric interventions, and assessment of foetal growth. Ultrasonography is the most reliable method for dating pregnancy, with foetal biometry being central to GA estimation. While parameters such as biparietal diameter and femur length are widely used, there is growing interest in evaluating additional foetal leg bones as potential predictors of gestational age.
Aim: To assess the relationship between foetal leg bone lengths measured by ultrasonography and gestational age, and to evaluate their usefulness in estimating gestational age.
Materials and Methods : This cross-sectional observational study included 456 pregnant women between 14 and 39 weeks of gestation. Ultrasonographic measurements of foetal femur, tibia, and fibula lengths were obtained using standardized techniques. Gestational age was calculated based on ultrasonographic dating. Statistical analysis included descriptive statistics, Pearson’s correlation, and linear regression analysis to evaluate the relationship between foetal leg bone lengths and gestational age.
Results: The mean gestational age of the study population was 26.36 ± 7.23 weeks. Mean femur, tibial, and fibular lengths were 4.61 ± 1.67 cm, 4.04 ± 1.47 cm, and 3.80 ± 1.38 cm, respectively. Femur length (r = 0.96, p < 0.001) and tibial length (r = 0.95, p < 0.001) showed a very strong positive correlation with gestational age, whereas fibular length demonstrated a moderate correlation (r = 0.59, p < 0.001). Regression analysis confirmed femur and tibial lengths as strong predictors of gestational age.
Conclusion: Foetal femur and tibial lengths show excellent correlation with gestational age and can be reliably used for gestational age estimation. Tibial length, in particular, may serve as a useful adjunct to femur length, especially when conventional parameters are difficult to assess.
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Suman Inkhiya
Senior Demonstrator, Department of Anatomy, RVRS medical College, Bhilwara
Ghanshyam Gupta
Former Senior Professor, Department of Anatomy, R N T medical College, Udaipur
N K Kardam
Senior Professor, Department of Radiology, R N T Medical College, Udaipur
