Correlation of Fetal Renal Volume with Gestational Age and Fetal Weight in 3rd Trimester Ultrasound

Objective:.To investigate the correlation between fetal renal volume, gestational age, and fetal weight in the third trimester to establish renal volume as a reliable marker for prenatal monitoring. Study design: It was a Cross-Sectional study. Place and duration of study: The study was conducted at Samar Diagnostic Lab, Lahore, from July to December 2024. Material and Methods: This study included 385 third-trimester pregnancies. Ultrasonographic measurements of fetal renal volume were performed for both kidneys. Descriptive statistics and tests of normality were applied to analyze growth patterns. Correlation analyses (Pearson and Spearman) evaluated relationships between renal volume, gestational age, and fetal weight, while regression models quantified predictive contributions of these parameters to renal volume. Results: Mean renal volumes for the right and left kidneys were 7.54 cm³ (SD = 2.14) and 7.55 cm³ (SD = 2.16), respectively. Gestational age (mean = 33.58 weeks) and fetal weight (mean = 2332.14 grams) exhibited strong correlations with renal volume (r > 0.94, p < 0.001). Regression analysis revealed that gestational age and fetal weight explained 92.6% (R2=0.926) and 90.9% (R2=0.909) of the variance in renal volume, respectively. Each additional week of gestation contributed 0.579 cm³ to renal volume, while each gram of fetal weight added 0.003 cm³.