We have known for more than half a century that good control of blood sugar (glucose) is important for the normal development of the unborn baby throughout pregnancy. During those years there has been much progress in advising women about optimal management of their diabetes during pregnancy. The key components in this management are physical exercise, diet, and insulin therapy. As the pregnancy progresses, exercise becomes more difficult and the emphasis is increasingly placed on diet and insulin dosage. The goal for this therapy is to maintain blood sugar as close to normal as possible. In this article Veikko Koivisto looks in particular at the importance of meal-time blood sugar control.