Antenatal diagnosis of cardiac defects and associated chromosomal anomalies

Aim: According to epidemiological studies on newborns, the association of c ongenital heart defects with chromosomal anomalies varies between 4 and 12% . Prenatally this rate is probably higher, due to antenatal death occuring in fetuses with chromosomal aberrations. The aim of the study was therefore to determine the rate and the distribution of chromosomal aberrations in p renatally detected heart defects. Patients and Method: Within a period of 7 years fetal echocardiography was performed on 2716 fetuses at high risk fo r CHD. The analysis of the fetal heart was achieved by the visualization of different planes. Once a heart defect was detected, karyotyping was perfor med after amniocentesis, cordocentesis or chorion villous sampling, or in a few cases postnatally from cord blood. Prenatal ultrasound findings were c onfirmed postnatally by ultrasound examination or, in case of abortion, sti llbirth or neonatal death, by autopsy. Results: A total of 203 fetal heart malformations were detected and 46 of them (22%) had associated chromosomal anomalies. 60% of all cases and 80% of the study group had extracardiac an omalies. Only eight out of the 46 pregnant women (17,5%) were older than 35 years. Eight out of the 15 fetuses with trisomy 18 had a ventricular septa l defect, 9/13 fetuses with trisomy 21 had an atrioventricular septal defec t and all 15 fetuses with monosomy X had a left heart outflow obstruction. No typical cardiac defects were found in the remaining 13 fetuses (5 trisom y 13, 2 triploidies, 6 miscellaneous). Of the 13 live births (23 terminatio ns of pregnancy and 10 intrauterine deaths) 6 children survived (46% and ov erall survival rate 13%). The following rates of associations with aneuploi dies were found: atrioventricular septal defect 55%, ventricular septal def ect and aortic coarction both 43%, tetralogy of Fallot and double outlet ri ght ventricle both 36%. In comparison, fetuses with isomerism, transpositio n of the great arteries and pulmonary atresia or stenosis had normal chromo somes, Conclusion: We conclude that the rate of association of heart defect s and chromosomal abnormalities is higher prenatally than in the neonatal p eriod and is approximately 22%. After detecting a fetal cardiac malformatio n, karyotyping is mandatory for the further management of pregnancy. The li kelihood of detection of an aneuploidy increases when some typical heart de fects are detected or when an association with extracardiac anomalies is fo und.