Hyperglycaemia in pregnancy is an increasingly common problem. It is essential to understand who, when and how to test for hyperglycaemia in pregnancy, particularly in early pregnancy, and how to manage pregnant women with hyperglycaemia, both during the pregnancy and postpartum.
The World Health Organization (WHO) refers to ‘hyperglycaemia first detected in pregnancy’ with subdivision into ‘diabetes mellitus in pregnancy’ and ‘gestational diabetes mel litus (GDM)’ (Figure).1 Although most women with hyperglycaemia first detected in pregnancy have GDM, some women have glucose levels in the range for diabetes outside pregnancy, which indicates possible undiagnosed diabetes (usually type 2 diabetes, occasion ally type 1 diabetes). It is particularly important to identify women with diabetes mellitus in pregnancy because the management, especially obstetric, differs from that of GDM. Not all women with diabetes mellitus in pregnancy will continue to have diabetes when retested postpartum.