A brand new chapter to this Edition of the Course Manual. Within increasing national awareness of the importance of optimum management of diabetes in pregnancy this chapter explores the underlying pathophysiology of both pre-existing and gestational diabetes. Key emergencies, such as diabetic ketoacidosis and hypoglycaemia, are also explored with clear management algorithms. Key learning points: Understand the different types of diabetes with their associated risks. Recognise the importance of supporting pregnant women to achieve optimal blood glucose levels to improve outcomes. Understand that careful surveillance and multi-professional support for women with diabetes in pregnancy reduces the risk of adverse outcomes, including diabetes emergencies. Gain confidence in the multi-professional management and prevention of diabetes emergencies in pregnancy including hypoglycaemia, hyperglycaemia and diabetic ketoacidosis. Recognise that prompt recognition and timely management of diabetes emergencies is essential to prevent potentially avoidable adverse outcomes.