Diabetes mellitus is a major medical complication of pregnancy and is associated with an increased risk of maternal and perinatal morbidity and mortality. Although recent advances have improved outcomes dramatically, the increased incidence of congenital malformations remains a significant problem. In the past, it was believed that pregnancy worsened microvascular complications, and women with vasculopathy were counseled to avoid or terminate pregnancies. Recent evidence suggests that normalization of blood glucose levels and current management strategies can lead to improved outcomes even in women with vasculopathy. Today, with the exception of coronary artery disease, women with diabetes may be counseled toward a more favorable outcome. This article discusses preconception planning and contemporary treatment methods.