As increasing numbers of children with congenital heart disorders reach adulthood, the family physician, cardiologist, and obstetrician will increasingly be called upon to give advice regarding the safety of pregnancy. This need has been further highlighted by the recognition that maternal mortality associated with cardiac disease is rising. Unfortunately, this field of practice remains relatively "evidence-sparse" with many management decisions being guided by anecdote and "best guess" common sense. Not surprisingly, this results in many fundamental controversies over the optimal care these patients should receive. This article highlights, through the use of case histories, some of these contentious areas, reflecting the different manifestations of congenital maternal cardiac disease and highlighting the limitations of our knowledge.