A group of chemical substances produced in the body by the adrenal glands. They have many actions, including regulation of carbohydrate, fat and protein metabolism, water and electrolyte balance, and the development and maintenance of sex characteristics. They can be made artificially and have many clinical uses – when given to pregnant women (antenatal corticosteroids), they can enhance fetal lung maturation, thus helping to reduce the incidence of respiratory distress in babies born preterm.