Perinatal changes in size of the fetal great arteries

Background and Objectives: At birth, the fetal circulation must immediately adapt to extrauterine life. Our goal was to evaluate perinatal changes in the size of the aorta (Ao) and pulmonary artery (PA), and to investigate factors influencing these changes. Subjects and Methods: Aortic and PA diameters were measured by echocardiography in 50 healthy term babies one day before and 4 to 5 days after birth. Results: Compared with prenatal measurements, the Ao increased (from 7.4±0.6 mm to 8.4±0.6 mm, p