['To determine the accuracy of the patent ductus arteriosus:left pulmonary artery ratio (PDA:LPA) on echocardiogram (ECHO) at 3-day postnatal in predicting spontaneous PDA closure in neonates ≤ 30 weeks gestational age (GA).', 'ECHOs were performed at 72 h to characterize PDA size as closed-to-small (PDA:LPA <0.5) or moderate-to-large (PDA:LPA ≥ 0.5) and at 10 days to determine spontaneous closure (defined as closed-to-small in the absence of medical and/or surgical treatment). Caretakers were blinded to results; treatment was based on standard care. Neonates were prospectively enrolled and stratified: <27 weeks (n=31) and 27 to 30 weeks (n=65).', 'Neonates <27 weeks with closed-to-small PDAs had 60% spontaneous closure vs 9% when moderate-to-large (positive predictive value (PPV) 60%, negative predictive value (NPV) 91%). Neonates 27 to 30 weeks had 95% spontaneous closure vs 27%, respectively (PPV 95%, NPV 73%). Inter-observer variability for the initial ECHO was 0.84.'] Do early echocardiographic prediction of ductal closure in neonates ≤ 30 weeks gestation?