Repeat doses of prenatal corticosteroids for women at risk of preterm birth for preventing neonatal respiratory disease

Background

It is not clear whether there is benefit in repeating the dose of prenatal corticosteroids for women who remain at risk of preterm birth after an initial course.

Objectives

To assess the effectiveness and safety of a repeat dose(s) of prenatal corticosteroids.

Search strategy

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (February 2007), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2006, Issue 4), MEDLINE (1965 to November 2006), EMBASE (1988 to November 2006) and Current Contents (1997 to November 2006).

Selection criteria

Randomised controlled trials of women who have already received a single course of corticosteroids seven or more days previously and are still considered to be at risk of preterm birth; outcomes compared for women randomised to receive a repeat dose(s) of prenatal corticosteroids, with women given no further prenatal corticosteroids.

Data collection and analysis

We assessed trial quality and extracted the data independently.

Main results

Five trials, involving over 2000 women between 23 and 33 weeks' gestation, are included. Treatment with repeat dose(s) of corticosteroid was associated with a reduction in occurrence (relative risk (RR) 0.82, 95% confidence interval (CI) 0.72 to 0.93, four trials, 2155 infants) and severity of any neonatal lung disease (RR 0.60, 95% CI 0.48 to 0.75, three trials, 2139 infants) and serious infant morbidity (RR 0.79, 95% CI 0.67 to 0.93, four trials, 2157 infants).

Mean birthweight was not significantly different between treatment groups (weighted mean difference (WMD) -62.07 g, 95% CI -129.10 to 4.96, four trials, 2273 infants), although in one trial, treatment with repeat dose(s) of corticosteroid was associated with a reduction in birthweight Z score (WMD) -0.13, 95% CI -26 to 0.00, 1 trial, 1144 infants), and in two trials, with an increased risk of being small for gestational age at birth (RR 1.63, 95% CI 1.12 to 2.37, two trials, 602 infants).

No statistically significant differences were seen for any of the other primary outcomes that included other measures of respiratory morbidity, fetal and neonatal mortality, periventricular haemorrhage, periventricular leukomalacia and maternal infectious morbidity. Treatment with repeat dose(s) of corticosteroid was associated with a significantly increased risk of caesarean section (RR 1.11, 95% CI 1.01 to 1.22, four trials, 1523 women).

Authors' conclusions

Repeat dose(s) of prenatal corticosteroids reduce the occurrence and severity of neonatal lung disease and the risk of serious health problems in the first few weeks of life. These short-term benefits for babies support the use of repeat dose(s) of prenatal corticosteroids for women at risk of preterm birth. However, these benefits are associated with a reduction in some measures of weight, and head circumference at birth, and there is still insufficient evidence on the longer-term benefits and risks.