The most frequent of them all are the many types of malformations of the cardiovascular system. Study of these conditions during the twentieth century took many... » 

The most frequent of them all are the many types of malformations of the cardiovascular system. Study of these conditions during the twentieth century took many forms, revolving about examination and analysis of their causes, genetic, nongenetic, and complex. To aid in unraveling the complexities of this causation, various influences on their frequency are considered, among them social conditions, maternal health, birthweight, newborn maturity. And of course the known and possible environmental bases of their occurrence are fully described. «