Judicious use of antenatal glucocorticoids: putting the risks into the balance.

The administration of a course of antenatal glucocorticoids (AG) to improve neonatal outcome after preterm birth is a prime example of evidence-based medicine, but the current clinical application of AG is too broad. AG override the glucocorticoid enzymatic placental barrier in order to elicit fetal lung maturation at a pre-physiological gestational age. Yet the maturation benefit is accompanied by a number of undesirable phenomena, most of which are transient (lasting for at least 24-48 h after the last injection). These include metabolic effects in both mother and fetus and signs of reduced fetal wellbeing. In addition, the fetal growth rate slows down depending on the number of AG courses. Multiple courses may increase the risk of cerebral palsy, as neonatal dexamethasone treatment does. There are no randomised trials on the benefit-risk balance of AG in pregnancies complicated by diabetes or intra-uterine growth restriction (IUGR). Animal studies indicate that AG are associated with an inadequate response to acute hypoxaemia and different brain development. Judicious use of AG includes avoidance of multiple courses, and a case-based -approach in pregnancies with (pre)gestational diabetes, IUGR or equivocal fetal condition, until more data become available. In addition, better prediction models of preterm birth are needed.