The fetal circulation and congenital heart disease

Abstract

The interactions between the postnatal development of the circulation and the presence of congenital cardiovascular malformations have been recognized for many years [1]. The changes in the pulmonary circulation after birth are crucial in altering the circulatory dynamics, resulting in clinical features of congenital cardiovascular anomalies, such as cardiac failure.. Because clinical disturbances were common in the early neonatal period, congenital cardiovascular anomalies were thought to have little adverse effect on the fetus. It was believed that the patterns of blood flow and the foramen ovale and ductus arteriosus shunts normally present in the fetus allowed the circulation to adapt adequately to the presence of cardiovascular malformations. However, in recent years, ultrasound studies of human fetuses and experimental studies of fetal lambs with simulated lesions have demonstrated that congenital cardiac anomalies may drastically affect the fetal circulation and fetal development and even survival. Furthermore, they may induce circulatory changes that profoundly alter normal adaptation after birth.