CORRELATION BETWEEN FETAL FOOT LENGTH AND HUMERUS LENGTH FOR THE ESTIMATION OF GESTATIONAL AGE IN SECOND AND THIRD TRIMESTER

Background: Gestational age (GA) is a critical parameter in obstetric care, guiding clinical decision-making, fetal monitoring, and estimating the expected date of delivery (EDD). Various biometric parameters, including biparietal diameter (BPD), femur length (FL), head circumference (HC), and abdominal circumference (AC), are conventionally used for GA estimation. However, alternative fetal measurements such as fetal foot length (FFL) and fetal humerus length (FHL) have shown potential in improving GA assessment, particularly in the second and third trimesters. Objective: To determine the correlation between fetal foot length and fetal humerus length with gestational age during the second and third trimesters using ultrasonographic assessment. Methods: A cross-sectional study was conducted at Bashir Diagnostic Hospital, Toba Tek Singh, over a duration of nine months. A total of 383 pregnant women with singleton pregnancies and known last menstrual period (LMP) were included using a convenient sampling method. Ultrasonographic measurements of FFL and FHL were obtained using a Toshiba Aplio XG ultrasound machine. Gestational age was estimated based on LMP, BPD, AC, and FL, and correlations with FFL and FHL were analyzed using Pearson’s correlation coefficient. A significance level of p < 0.01 was considered statistically significant. Results: A strong positive correlation was observed between GA by LMP and FHL (r = 0.901, p < 0.01) and GA by LMP and FFL (r = 0.895, p < 0.01). GA by BPD correlated significantly with FHL (r = 0.909, p < 0.01) and FFL (r = 0.915, p < 0.01). GA by AC showed significant associations with FHL (r = 0.900, p < 0.01) and FFL (r = 0.894, p < 0.01). Similarly, GA by FL exhibited strong correlations with FHL (r = 0.899, p < 0.01) and FFL (r = 0.891, p < 0.01). Conclusion: Fetal humerus length and fetal foot length demonstrated strong correlations with gestational age and can be effectively utilized for GA estimation in the second and third trimesters. These parameters serve as reliable alternatives when conventional measurements may be limited, contributing to improved prenatal assessment and fetal growth monitoring.