Antenatal steroid

Antenatal steroids (or antenatal corticosteroids) are medications given to pregnant women expecting preterm delivery. They have been shown to reduce the morbidity and mortality of hyaline membrane disease.[1] They have also been shown to have definite beneficial effect even in conditions of preterm premature rupture of membranes (PPROM).[2]

The effectiveness of antenatal corticosteroids in preventing neonatal hyaline membrane disease and reducing mortality in premature infants was first demonstrated by Sir Graham Liggins and Ross Howie in 1972.[3]

Current evidence suggests that giving antenatal corticosteroids reduces late miscarriages and baby deaths. The baby is also less likely to have respiratory distress syndrome (difficulty breathing), or need assistance breathing (mechanical ventilation).[4] They are also less likely to have (bleeding on the brain) intraventricular hemorrhage,[5][6] NEC, or systemic infections (infections affecting the whole body) in the first two days of their life.[7] Steroids do not appear to increase the number of women who develop infection of the fetal membranes (chorioamnionitis) or of the womb (endometritis).[8] This research evidence is mostly from mid- to high-income countries. However, there is not a lot of research into giving antenatal corticosteroids to women in low-income countries where infections are more common. More research is needed to find out the effects of these steroids on women and babies in low-income countries.[9]

Dexamethasone and betamethasone are the corticosteroids used for the purpose although the former is recommended over the latter based on its efficacy, safety, wide availability, and low cost[10] in spite of some counter-logic.[11] Betamethasone, on the other hand, is preferred over dexamethasone because it is thought to have better prophylaxis of brain softening of premature fetus.[12] They are used with the intention to help the lungs of a premature fetus develop before the fetus comes out.[13] They are given when the fetus is expected to be delivered within 24 to 48 hours. Treatment consists of 2 doses of 12 mg of betamethasone given intramuscularly 24 hours apart or 4 doses of 6 mg of dexamethasone given intramuscularly 12 hours apart. Optimal benefit begins 24 hours after initiation of therapy and lasts 7 days.[14][15] Antenatal steroids are currently used up to 36 weeks in some parts of the world obstetric practice.[16]

The time between administration of steroids and delivery may alter the effectiveness of the steroids.[17]