Despite their low prevalence (2 to 4 percent of all live births), congenital anomalies are the leading cause of perinatal mortality and infant morbidity (1).
Congenital heart disease (CHD) accounts for 30 to 50 percent of these deaths. Prenatal diagnosis and management are therefore important for both fetal prognosis and decreasing economic burden of family and society. Fetal congenital heart disease involves an abnormality of the heart, whether it is a structural defect, a problem with the fetal heartbeat, or a functional problem with the heart systole or diastole (2). CHD is a multifactorial, complicated disorder of unclear etiology and poor prognosis, so prenatal diagnosis is vital. Generally, the full spectrum of cardiac anomalies seen in a postnatal population can be detected in the fetus. Heart defects, such as atrial septal defect, ventricular septal defect and other complex conditions such as transposition of the great arteries and tetralogy of Fallot, can be successfully managed after birth. Early diagnosis during fetal life in these cases by ultrasound screening and fetal echocardiography not only identifies the cardiac lesion but may also detect associated abnormalities. This provides information regarding the decision of termination or further management of the pregnancy.
In fact, many studies show that fetal cardiac screening was found to impact on the prevalence and types of congenital heart disease because many of the affected pregnancies (23 percent of diagnosed cases) were terminated. Other cardiac defects require management while the baby is still in the womb. For instance, structural abnormalities, such as Aortic or Pulmonary valvular stenosis, can interfere with development of the pumping chambers, leading to devastating problems after birth, which often require multiple complex open-heart surgeries and, even when successful, result in distinctly abnormal function (the so-called ‘single ventricle physiology’). In these cases, relief of the obstruction by invasive in utero cardiac intervention (e.
g. aortic or pulmonary balloon valvuloplasty) may allow more normal development of the ventricle, thus resulting in a very different outlook for the infant after birth. In a similar manner, abnormalities of the heart’s conduction system referred to as “dysrhythmias” or “arrhythmias”, such as supraventricular tachycardia or fetal bradycardia (heart block), can be fatal to the fetus but if treated by transplacental medical therapy can be controlled or cured with a very good outcome.
In conclusion, it is safe to say that most fetal heart abnormalities, whether structural, functional or conductive, that are diagnosed prenatally have a better outcome. This can be a result of early decision making regarding the pregnancy`s termination or fetal interventions such as transplacental medication therapy or intrauterine surgery. Early detection and treatment of these conditions are therefore vital to both reduce their case fatality rate and improve the outcome and quality of postnatal life.