Can we suspect fetal down syndrome by heart evaluation during the second half of pregnancy?

Thirty fetuses with Down syndrome, who had detailed fetal echocardiography and sonography at the tertiary center with videotape recordings, were retrospective analyzed by one observer with a specially prepared flow sheet. The mean gestational age of the fetuses at the time of the study was 31 +/- 5.6 (minimum 21, maximum 39) weeks. The 'main' fetal abnormalities were congenital heart defect (CHD): in 13 cases (43.3%) an abnormal 4-chamber view was recorded, including 6 cases (20%) of isolated CHD and 7 (23.3%) of coexisting CHD + extracardiac malformation. Of the 13 cases of CHD, there were 12 cases of atrio-ventricular canal and 1 case of ventricular septal defect. Normal heart anatomy was recorded in 17 cases (56.7%), including 2 with tricuspid value regurgitation. From the videotape recordings also some 'minor' abnormalities were noticed in a few cases such as: femur length shortening; sandal gap; pericardial effusion; macroglossia; echogenic bowel; absent diastolic flow in the umbilical artery, and others. The prevalence of CHD in the study group was similar to the prevalence of CHD in the comparison group of 20 newborns with Down syndrome, born during the same period of time at the same institution, who had not had prenatal scanning at all (chi2, p > 0.05).

(1) the main 'major' abnormality which might be detected in a fetus with Down syndrome after 20 weeks of pregnancy is CHD, which was presented in 43.3% of this series; (2) the presence of any extracardiac malformation should prompt the sonographer for detailed heart evaluation, and (3) fetal echocardiography may increase the accuracy of 'genetic sonogram' in Down syndrome.