Pre-existing type I and type II diabetes in pregnancy

Women with pre-gestational diabetes are high-risk pregnancies. Hyperglycaemic is toxic to the developing fetus and is associated with a higher incidence of congenital malformation, miscarriage, macrosomia and stillbirth. Complications can be reduced with tight glycaemic control, and management should ideally start pre-conceptually. During pregnancy a woman’s insulin requirements change and those managed pre-pregnancy on diet or oral medication may need to start insulin. Pre-gestational diabetics require close maternal and fetal monitoring, including screening for the progression of maternal diabetic complications such as retinopathy and nephropathy, and fetal growth scans. Their pregnancies are complex and a multidisciplinary approach should be used. In this article we will discuss the background physiology, the effect of pregnancy on diabetes, the potential fetal and maternal complications, and how these can be minimized by intensive management from pre-conception to the post-natal period, including the contribution of recent studies and guidelines.