Since Liggins and Howie first published their work, numerous studies have shown that corticosteroids significantly decrease perinatal mortality and morbidity, without complication for the mothers and child. Corticosteroids should be prescribed in case of threatening premature birth. Imminent delivery premature rupture of the membranes and gestationnal age over 34 weeks are not contraindications to prescription, as corticosteroids can be safely given all in these circumstances. Theoretically, more than half of premature neonates should have been treated with corticosteroids. Actually, only 20% or less are currently treated. The cost-effectiveness ratio of an antenatal corticosteroid policy would be extremely positive: more than 1,500 prenatal deaths could theoretically be avoided in France annually and the overall cost of neonatal care would decrease by 10%.