Gestational diabetes is a carbohydrate intolerance that is first detected in pregnancy and usually disappears after birth. It is characterised by fasting and post-prandial hyperglycemia. The immediate maternal and fetal consequences of gestational diabetes on pregnancy are well known. During the last decade, there has been increasing evidence suggesting that women with gestational diabetes are at increased risk of developing diabetes and metabolic syndrome in later life. A meta-analysis of 20 cohort studies involving 675 455 women reported that women with gestational diabetes had a 7.5-fold increased risk of developing type 2 diabetes compared with those women who had a normoglycemic pregnancy (RR 7.43, 95% CI 4.79-11.51). Women with a history of gestational diabetes had a relative risk of 4.69 within 5 years of pregnancy and this risk doubled to 9.34 after 5 years.