Reference ranges of fetal adrenal gland and fetal zone volumes between 24 and 37 + 6 weeks of gestation by three-dimensional ultrasound

AbstractObjective: To establish reference ranges of the fetal adrenal gland (AG) and fetal zone (FZ) volumes using three-dimensional ultrasound (3DUS).Methods: We performed a prospective cross-sectional study with 204 normal singleton pregnancies between 24 and 37 + 6 weeks of gestation. The fetal AG and FZ volumes were obtained using the virtual organ computer-aided analysis method with a 30° rotation. To establish reference ranges as the function of gestational age (GA), quantile regression was performed with the adjusted coefficient of determination (R2). Intra- and inter-observer repeatability was performed using the intraclass correlation coefficient (ICC).Results: The mean results of fetal AG and FZ values were 0.42 cm3 (0.04–1.22) and 0.10 cm3 (0.02–0.47), respectively. The best-fit quantile regression models for fetal AG and FZ volumes as the function of GA were in first-degree models: AG = −0.937 + 0.041 × GA (R2 = 0.124) and FZ = −0.201 + 0.009 × GA (R2 = 0.127), respectively. We observed good i...