As young maternal age is associated with an increased risk of unfavourable fetal outcome, teenage mothers need improved prenatal care and increased observation during labour. In addition, improvement of the social environment of adolescents and the prevention of teenage pregnancies should be recommended.

Objective: To find connection between the type of congenital heart malformations and twin pregnancies. Method: Retrospective analysis of data of fetal cardiology database between 1 January 1996 and 30 November 2003. Results: In single pregnancies 455 and in twin pregnancies 31 severe congenital heart malformations were diagnosed prenatally. In monozygotic twin pregnancies 36% of heart malformations were pulmonary stenosis and 45% endocardial fibroelastosis, which is significantly higher than in single pregnancies. In dizygotic twin pregnancies Ebstein malformation was significantly more frequent than in single pregnancies. With the exception of Ebstein malformation in dichorionic and dizygotic twin pregnancies the cardiac malformations were similar to the ones in single pregnancies. Conclusions: The twin pregnancy alone can be considered as indication for fetal echocardiography. The type of congenital heart malformations detected in monochorial twin pregnancies was different from those found in single, dizygotic or dichorionic twin pregnancies. Chorionicity seems to be more important than zygosity.