One in 250 pregnancies in the UK involves diabetes. The majority of cases (87.5%) are gestational diabetes, 7.5% are type 1 and 5% are type 2 diabetes. Diabetes in pregnancy is associated with a five fold increase in risk of stillbirth and a two-fold increased risk of congenital defects compared with the general maternity population. Women with gestational diabetes have a significant lifetime risk of developing type 2 diabetes, hence diabetes screening must be undertaken on an annual basis in primary care.