[Antenatal corticosteroids: neonatal effects of a second course]

Because they might not be efficient in reducing neonatal morbidities associated with preterm birth after 7 days of exposure, antenatal corticosteroids have been systematically repeated every week or every 2 weeks in the late 90's. Evaluation of these strategies by randomized trials demonstrated, for the neonates exposed to multiple courses, short-term neonatal benefits, mainly pulmonary, but also alterations of fetal growth and potential impairments in neurodevelopmental outcomes, without benefits at 2 years of age. This is the reason why systematic repetitive doses of antenatal corticosteroids have been stopped and has emerged the concept of rescue course in which betamethasone is given only when delivery has again become likely. It can be concluded from the only two randomized trials having evaluated this strategy that antenatal corticosteroids rescue courses might be beneficial in reducing acute pulmonary morbidity, without noticeable effects on fetal growth. Scientific data suggesting the efficacy and innocuousness of antenatal corticosteroids rescue courses in the early neonatal period are now available, however, they should be further confirmed by new randomized trials and follow up studies before this strategy can be recommended for a daily clinical practice.