In women with type 1 diabetes mellitus, meticulous glycaemic control, before and during pregnancy, usually results in a healthy baby. However, national and regional audits show poorer outcomes than the background population. Despite great efforts by mothers and their Diabetes Care Teams, the babies are often large for gestational age, delivered early by Caesarean section (64%), and spend some time in intensive care. In Scotland, perinatal mortality in diabetic pregnancy has reduced in recent years, but offspring continue to have more congenital abnormalities than the non-diabetic population. The risk of stillbirth and infant mortality are also in excess of the non-diabetic population. In clinical practice, a comprehensive pre-pregnancy and pregnancy care package delivered by a multidisciplinary team to address all risk factors will reduce congenital anomalies and other adverse outcomes. Maintaining very tight control throughout pregnancy can prove difficult. The management of acute and chronic complications of diabetes is challenging and requires individualised solutions underpinned by knowledge of maternal physiology and the impact of maternal metabolism on the developing fetus and newborn.