**4.1. When and how to use corticosteroids for lung maturation**

The treatment consists in betamethasone administration intramuscularly two 12 mg doses 24 hours apart or dexamethasone intramuscularly four 6 mg doses every 12 hours.

A single course of corticosteroids must be considered in twin pregnancy between 24th and 33rd week that have high risk of preterm delivery within 7 days, including for those with ruptured membranes and if the first course was administered previously more than 14 days. It also may be considered for pregnant women starting at 23 0/7 weeks of gestation who are at risk of preterm delivery within 7 days, based on a family's decision regarding resuscitation. A rescue course of corticosteroids can be considered before 7 days from the first dose if there is some clinical indication for that [51].

A new recommendation from the ACOG suggests that in pregnancy during the 34–37th week, the use of corticosteroids could be beneficial, even during this late period of pregnancy, regardless of the number of fetuses [7, 52].

Administration of corticosteroids can be considered in twin pregnancy between the 34th and 37th week which are in risk of preterm birth within 7 days and which have not received the previous course of betamethasone [52].

Unfortunately, according to the WHO, in Brazil only 30% of preterm birth received antenatal corticosteroids to lung maturation between 2010 and 2011 [53], whereas several pregnancies received unnecessary corticosteroids, without real indication for that [54].
