Single versus multiple antenatal steroids in threatened preterm delivery: more benefit or harm?
- 1Neonatal Intensive Care Unit, Rosie Maternity Hospital, Addenbrooke’s Hospital, Cambridge, UK
- 2Department of Obstetrics and Gynaecology, Cambridge University, Cambridge, UK
- Dr Gordon C S Smith, Department of Obstetrics and Gynaecology, Cambridge University, Rosie Maternity Hospital, Cambridge CB2 2SW, UK; gcss2{at}cam.ac.uk
- Accepted 1 September 2008
- Published Online First 6 October 2008
The first demonstration that antenatal maternal glucocorticoid treatment reduced neonatal morbidity was reported by Liggins and Howie in 1972.1 In the following two decades antenatal corticosteroid prophylaxis gradually found its way into clinical practice and had become an accepted part of the standard care by the early 1990s.2 3 It clearly reduces overall neonatal mortality, the risk of respiratory distress syndrome (RDS) and the need for respiratory support.4 It also decreases the risk of other complications of prematurity, including intraventricular haemorrhage (IVH) and necrotising enterocolitis but not bronchopulmonary dysplasia (BPD). The current recommendation is to give two doses of 12 mg betamethasone, 24 h apart, to women who may deliver within 7 days and are less than 35 weeks pregnant.5–7 Most benefit is seen when delivery follows the second dose by more than 24 h; however, even an incomplete course reduces neonatal morbidity and mortality.8
There is a marked reduction in the apparent beneficial effects of antenatal steroids (ie, glucocorticoids) if the interval between administration and delivery exceeds 7 days.4 This led to the evaluation of multiple steroid treatments among women who remained at high risk of preterm birth.9 However, animal data and observational human studies demonstrated possible adverse effects of repeated doses of glucocorticoids. Moreover, evidence emerged of severe adverse effects of postnatal steroids, particularly on growth and neurodevelopmental outcome.10 This resulted in guidelines advising against routine use of repeat steroid courses except in clinical studies, in both the UK and the USA.5 11 In this paper, we discuss the data from a series of randomised controlled trials (RCTs) of repeat steroids and the implications for care of women at sustained risk of preterm birth.
BENEFICIAL EFFECTS
The physiological consequences of repeated antenatal steroid exposure have been extensively studied in …
