ABSTRACT
In this chapter, we discuss the international incidence of congenital malformations and chromosomal anomalies in twin births, based on data gathered from several birth defects monitoring programs. We also present recent data on trends in congenital malformations and/or chromosomal anomalies in twin live births in the United States between 1989-91 and 1998-2000. Finally, we discuss the impact of these malformations and anomalies on infant mortality in United States twin live births between 1989-91 and 1998-2000.
