Objective: To evaluate the detection and accuracy of fetal echocardiography for congenital heart defects among high-risk populations.
Methods: A prospective observational study of prenatal diagnosis of congenital heart disease was conducted in two tertiary obstetrics and gynecology hospitals between January 2003 and December 2004. Consecutive fetuses at risk of congenital heart disease underwent detailed fetal echocardiography during the study period. B-mode and colour/pulsed Doppler flow imaging were used in all cases. Follow-up was sought for all pregnancies. Indications for referral, maternal and gestational age at diagnosis, as well as prenatal and postnatal diagnosis were recorded prospectively. By comparing prenatal and postnatal diagnoses, sensitivity, specificity, and predictive values were estimated.
Results: A series of 2063 high-risk fetuses underwent detailed fetal echocardiography during the study period. The mean gestational age at examination was 26.5 weeks, ranging from 16 to 42 weeks. The most common indications for fetal echocardiography were advanced maternal age (31.7%), fetal arrhythmias (13.5%) and maternal infections (10.4%). Forty-three cases of fetal congenital heart disease were detected. The mean gestational age at prenatal diagnosis was 27.3 weeks ranging from 16 to 40 weeks. There were 3 false-negatives and 1 false-positive. The sensitivity, specificity, positive and negative predictive values were 92.1%, 99.9%, 97.2%, and 99.8%, respectively. Diagnostic accuracy was 86.1%. A cardiac defect suspected on routine prenatal sonography accounted for the highest proportion of abnormal cases (67.4%). As for pregnancy outcome, there were 24 (52.1%) terminations; 2.2% died in utero, 13% postnatally, and 28.3% survived.
Conclusions: (1) Fetal congenital heart disease can be identified reliably by prenatal echocardiography. (2) Possible congenital heart disease or suspected heart defect noted on a screening obstetric sonogram is an important indication for fetal echocardiography. (3) A sequential segmental approach is critical for correct evaluation of the cardiac malformation. (4) The outcome of the patients with congenital heart disease is poor and a multidisciplinary approach is needed to the parental counseling and perinatal management planning.