Congenital malformations are worldwide occurrences, they know no national borders, do not distinguish between races, ethnicities, rich or poor. These severe physical abnormalities, present at birth, happen more often than is usually realized, once in every 33 births. They strike every part of the body, limbs, head, heart, and all others. The most frequent of them all are the many types of malformations of the cardiovascular system, the heart and its blood vessels, which happen in about once in every 250 births. 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.The relation of infant death to cardiovascular malformation is noted; and puzzlement that the level of such deaths had not kept pace with the reduction of infant death itself and of that associated with other kinds of malformations during this period. An introductory record of the history of perinatal mortality in the last three centuries gives foundation for the discussion of death in contemporary decades.