How do other illnesses affect heart abnormalities?

Certain other illnesses may increase your or your child's risk of developing a heart abnormality. If you have rubella (German measles) or diabetes during your pregnancy, your child is more likely to develop a congenital heart defect in the womb. Rheumatic fever and rubella, which North American medicine has virtually eliminated, may cause heart valve disorders or abnormal heart rhythms in adults.