Antenatal corticosteroids: is more better?

Abstract

Ever since the landmark observations by Liggins that corticosteroids given to pregnant sheep were associated with accelerated lung maturation in the fetus, 1 Liggins GC Premature delivery of foetal lambs infused with glucocorticoids. J Endocrinol. 1969; 45: 515-523 Crossref PubMed Scopus (627) Google Scholar several studies have shown the beneficial effects, on the fetus, of an antenatal course of corticosteroids for women undergoing premature labour. A Cochrane systemic review 2 Crowley P Prophylactic corticosteroids for preterm delivery (Cochrane Review). The Cochrane Library, Issue 4. Update Software, Oxford1999 Google Scholar indicates that a single antenatal course of corticosteroids reduces the occurrence of respiratory distress syndrome (RDS), intraventricular haemorrhage (IVH), and neonatal mortality in babies born prematurely. However, until the US National Institutes of Health Consensus Conference in 1994, physicians were slow to adopt this treatment for women at increased risk of premature delivery. The importance of corticosteroids given antenatally has led to several detailed clinical surveys, which have all identified the spread of the practice of prescribing multiple antenatal courses of corticosteroids when the risk of preterm delivery is judged to persist. For example, a recent survey of obstetric units in the UK 3 Brocklehurst P Gates S McKenzie-McHarg K Alfirevic Z Chamberlain G Are we prescribing multiple courses of antenatal corticosteroids? A survey of practice in the UK. Br J Obstet Gynaecol. 1999; 106: 977-979 Crossref PubMed Scopus (121) Google Scholar showed that 98% of such units are prescribing repeated courses. This trend is worrying because there is no good evidence to support an advantage of multiple over single courses, 2 Crowley P Prophylactic corticosteroids for preterm delivery (Cochrane Review). The Cochrane Library, Issue 4. Update Software, Oxford1999 Google Scholar whereas there is an increasing body of evidence suggesting that fetal exposure to corticosteroids may have long-term adverse consequences for childhood and adult development.