Objective:To assess arterial morphology and mechanics in preterm infants with fetal growth restriction (FGR) compared with those appropriate for gestational age (AGA) in the early neonatal period.Study design:This observational study involved 20 preterm FGR infants (28 to 32 weeks) of gestational age (GA) and birth weight (BW) <10th centile and 20 preterm AGA infants. Vascular ultrasound was performed to measure aortic properties.Results:GA and BW of FGR and AGA infants were 29.8±1.3 vs 30±0.9 weeks (P=0.78) and 923.4±168 vs 1403±237 g (P<0.001), respectively. At 10.5±1.3 (s.d.) days after birth, blood pressure (systolic 51±3 vs 46±4 mm Hg, P<0.001) and maximum aorta intima-media thickness (621±76 vs 479±54 μm; P<0.001) were significantly higher in FGR infants. Arterial wall stiffness and peripheral resistance were also increased in the FGR infants (2.36±0.24 vs 2.14±0.24, P=0.008 and 22.2±5 vs 13.7±2.3 mm Hg min ml -1, P<0.001), respectively. Significant correlations between vascular mechanics and cardiac function were observed (resistance vs E/E', r=0.7 and Tei index, r=0.79).Conclusion:Maladaptive arterial-ventricular coupling was noted. Early detection may aid in early therapeutic strategies such as afterload reduction.