ABSTRACT
Introduction Almost 50 years ago, the important role of the change in pulmonary circulation normally occurring after birth in influencing the manifestations of many congenital cardiovascular malformations was recognized.1 It is now appreciated that changes not only in the pulmonary circulation, but also in other sites in the circulation after birth, may have profound effects on the hemodynamics and clinical manifestations postnatally. In addition, the effects of various congenital cardiovascular lesions on the development of the pulmonary vasculature after birth were documented. The interrelationships between prenatal development of the circulation and the presence of congenital cardiovascular malformations had not previously been appreciated, but with the increasing application of fetal echocardiography, it is now becoming evident that congenital cardiovascular malformations may also have profound effects on normal development of the circulation in the fetus, and the effects may be progressive with intrauterine growth of the fetus. Furthermore, developmental changes in the circulation during fetal life may affect the manner in which cardiovascular malformations present, as well as the time during gestation that the changes become manifest.
