Abstract

ROLE OF FOETAL THIGH CIRCUMFERENCE IN ESTIMATION OF BIRTH WEIGHT BY ULTRASOUND AT TERM GESTATION

Dr. Kurmala Pravallika M.B.B.S. and Dr. A.C. Ramesh MS.

ABSTRACT

Background: Accurate foetal weight estimation is critical for managing neonatal survival, preterm delivery decisions, and identifying intrauterine growth restriction (IUGR) or macrosomia. Prospective studies comparing Hadlock’s formula (BPD, HC, AC, FL) and Vintzileos’ formula (with TC) show the latter’s superiority. 9 Postnatal thigh circumference strongly correlates with ultrasound thigh circumference. Vintzileos et al. introduced thigh circumference (TC) measurements to better capture soft tissue mass, enhancing accuracy in growth-abnormal foetuses. The present study was planned with these in mind. Objective: To assess the relative usefulness of ultrasound foetal parameters such as BPD, FL and AC when compared with clinical methods in assessing foetal weight. To evaluate the accuracy and usefulness of predicting birth weight by measuring foetal thigh circumference by ultrasound.Methods: This Prospective, cross-sectional descriptive study sought toexamine the relationship between various foetal biometric parameters and birth weight outcomes. The research was conducted with 100 pregnant women who were recruited from hospitals associated with J.J.M. Medical College in Davangere, India. The studyparticipants were selected based on specific criteria that allowed the researchers to investigate various foetal measurements, including head circumference (HC), femur length (FL), mid-thigh soft tissue circumference, and abdominal circumference (AC). These biometric measurements are crucial in evaluating foetal growth, especially in identifying potential complications such as macrosomia (large birth weight) or intrauterine growth restriction (IUGR), which can affect labour and delivery outcomes. RESULTS: In the study, all pregnancies were between 37 and 40 weeks of gestation, considered full-term and ideal for delivery, had a cephalic presentation and a longitudinal lie (vertical), the most favorable positions for a natural delivery 96% of the cases had normal head Femur length (FL), was normal range (6.8–7.3 cm) for 94% birth weights among the participants. The majority of babies (89%) had normal weight range Abdominal circumference was normal 95% from 30.0 to 33.0 cm AUC for abdominal circumference 0.85.Mid-thigh circumference 0.82, CONCLUSION: The Vintzileos formula shows lesser error compared to Hadlock’s formula, especially in higher birth weights.

Keywords: Vintzileos formula; Hadlock’s formula; Femur length; Mid-thigh circumference; Birth weight.