Changes in the aortic and pulmonary diameters in a fetus with hypoplastic left heart syndrome

We diagnosed hypoplastic left heart syndrome in a 26-week-old fetus using fetal echocardiography. Color Doppler ultrasonography was helpful for evaluating the structural abnormalities. The diameters of the aorta and the pulmonary artery were measured periodically from 26 to 38 weeks of gestation. Aortic diameter was below the normal range throughout gestation. The diameter of the pulmonary artery was normal at 26 weeks of gestation but gradually dilated and was abnormally dilated after the 36th week of gestation. Here we discuss the cause of enlarged pulmonary artery in fetal hypoplastic left heart syndrome.