Fetal echocardiography

Since the first report of fetal echocardiography in 1972 by Winsberg, several advances in ultrasound technology have occurred allowing detailed evaluation of cardiac anatomy in the second trimester fetus. Fetal echo is indicated in high risk pregnancies where the chances of fetus having a congenital heart disease (CHD) are likely to be high e.g., in fetus with extracardiac anomalies picked up on obstetric ultrasound, those with a history of CHD in family, maternal diabetes (especially insulin dependent), maternal connective tissue disorder etc. The reported sensitivity of fetal echo has ranged from 4-96% in various series depending upon the equipment, level of training, study design and examination technique. Although many CHD can be detected in four chamber view, an important group malformations that would need early intervention are likely to be missed. Hence a detailed echocardiographic examination including the outflow views must be done. Defects like atrial septal defect and patent ductus arteriosus cannot be diagnosed in fetal echo, as these are part of normal fetal physiology. Other CHD like coarctation of aorta, small ventricular septal defects, mild valvular stenosis, partial anomalous pulmonary venous drainage are also difficult to diagnose. Ultrasound assessment of fetus, however, has a clear role in the diagnosis, monitoring and management of fetuses with sustained arrhythmias. Prenatal diagnosis of CHD helps in planning the optimal management of the baby e.g. a fetus with a ductus dependent lesion can be planned to be delivered in a tertially care centre for stabilisation and early initiation of prostaglandin therapy to avoid acidosis and organ damage. Future of fetal medicine lies in fetal cardiac surgery for which echocardiography will play a very important role.