Babies born early are at risk of death, lung problems (respiratory distress syndrome) and bleeding of the brain (intraventricular haemorrhage). Corticosteroids are given to the mother to help stop these problems occurring and there is high-quality evidence that they are effective in preventing many of these problems. These drugs work by maturing the baby's lungs before birth. There are different types of corticosteroids and they can be given in different ways and in different doses. Since there is no clear or agreed best type or dose, hospitals may vary in how they give this drug.
Most trials have compared the two most commonly used corticosteroids before early birth, dexamethasone and betamethasone. In this review of ten trials, nine trials compared dexamethasone and betamethasone; and one trial compared two different ways of giving dexamethasone. We found that dexamethasone and betamethasone showed similar results, although there was less bleeding of the brain (but perhaps more frequent admission to the neonatal intensive care unit) for dexamethasone compared with betamethasone. On the basis of one trial, giving dexamethasone by injection (intramuscularly) may be better than giving the drug to the mother by mouth. We need more studies to establish which is the best drug and which is the best way to give it, and babies in these trials need to be followed up over a long period to monitor any effects on child and adult development.