van Ark AE, et al. - In this study, researchers explored reference values of cardiac valve annulus diameters in a cohort of extremely preterm very-low-birth-weight neonates and link these to patient characteristics. Using 2-dimensional echocardiography, valve diameters of 376 infants of < 32 weeks’ gestation and with a birth weight of ≤ 2,000 grams were measured. Researchers assessed correlations between valve diameters and patient characteristics. They provided ready-to-use reference values for cardiac valve annulus diameters for extremely preterm infants. A moderate correlation was found between birth weight and valve diameter.