SONOGRAPHIC INTER AND INTRA-OBSERVSER VARIABILITY IN THE MEASUREMENTS OF FEMUR LENGTH AS A PARAMETER FOR GESTATIONAL AGE DETERMNATION IN TARABA STATE SPECIALIST HOSPITAL, JALINGO.

ABSTRACT Background: Gestational age determination is a critical aspect of prenatal care and fetal assessment. One of the parameters commonly used for this purpose is femur length. However, the precision and reliability of femur length measurements can vary between sonographers and over time, which can impact its clinical and research utility. Objective: To assess and evaluate inter- and intra-observer variability in the measurement of femur length as a parameter for gestational age determination, compare its accuracy with other feotal parameters. Materials and methods: A prospective cross-sectional study was conducted at the Radiology Department of Taraba State Specialist Hospital, Jalingo, aimed to evaluate the inter- and intra-observer variability in femur length measurements and their accuracy in determining gestational age. The study included apparently normal pregnant subjects in their second and third trimesters referred for cyesis scan, and data was collected from 400 subjects who consented to participate. The measurements were obtained using a Mindray digital ultrasonic diagnostic imaging system. The scanning technique was trans-abdominal, and standard measurement protocols were followed. Results: Findings from this study showed that the inter-observers (observer A and B) mean measurement of femur length was very strong positive correlation (r=0.9949) and high inter- observer correlation coefficient after measuring the femur length. The intra-observers (A and B) relationship of femur length measurement at two different time suggest a very strong positive correlation (r = 0.9957 and 0.9852 respectively).finding also showed that the relationship between the femur length (FL) measurement for both observer (A and B) shows strong positive correlation with Bi-parietal diameter (BPD) and Abdominal circumference (AC). Conclusion: Findings from this study highlighted the main issue in obstetrics sonography, which is the issue of operator dependability ‘competence’. It demonstrates strong and consistency in femur length measurement between and within observers, indicating low variability in sonographic measurements of femur length for gestational age determination. The high correlation coefficients underscore the reliability of femur length as a parameter alongside BPD and AC in estimating gestational age during pregnancy. These result support the use of femur length as a valuable tool in clinical practice for assessing fetal growth and development. However, the issue of competence and quality assurance of the procedure must not be left out. Keywords: ultrasound, femur length, gestational age.