Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth

Corticosteroids given to women in early labour help the babies' lungs to mature and so reduce the number of babies who die or suffer breathing problems at birth.

Babies born very early are at risk of breathing difficulties (respiratory distress syndrome) and other complications at birth. Some babies have developmental delay and some do not survive the initial complications. In animal studies, corticosteroids are shown to help the lungs to mature and so it was suggested these drugs may help babies in preterm labour too. This review of 21 trials shows that a single course of corticosteroid, given to the mother in preterm labour and before the baby is born, helps to develop the baby's lungs and reduces complications like respiratory distress syndrome. Furthermore, this treatment results in fewer babies dying and fewer common serious neurological and abdominal problems, e.g. cerebroventricular haemorrhage and necrotising enterocolitis, that affect babies born very early. There does not appear to be any negative effects of the corticosteroid on the mother. Long-term outcomes on both baby and mother are also good.

Authors' conclusions: 

The evidence from this new review supports the continued use of a single course of antenatal corticosteroids to accelerate fetal lung maturation in women at risk of preterm birth. A single course of antenatal corticosteroids should be considered routine for preterm delivery with few exceptions. Further information is required concerning optimal dose to delivery interval, optimal corticosteroid to use, effects in multiple pregnancies, and to confirm the long-term effects into adulthood.

[Note: The 16 citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]

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Background: 

Respiratory distress syndrome (RDS) is a serious complication of preterm birth and the primary cause of early neonatal mortality and disability.

Objectives: 

To assess the effects on fetal and neonatal morbidity and mortality, on maternal mortality and morbidity, and on the child in later life of administering corticosteroids to the mother before anticipated preterm birth.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (30 October 2005). We updated this search on 30 April 2010 and added the results to the awaiting assessment section of the review.

Selection criteria: 

Randomised controlled comparisons of antenatal corticosteroid administration (betamethasone, dexamethasone, or hydrocortisone) with placebo or with no treatment given to women with a singleton or multiple pregnancy, expected to deliver preterm as a result of either spontaneous preterm labour, preterm prelabour rupture of the membranes or elective preterm delivery.

Data collection and analysis: 

Two review authors assessed trial quality and extracted data independently.

Main results: 

Twenty-one studies (3885 women and 4269 infants) are included. Treatment with antenatal corticosteroids does not increase risk to the mother of death, chorioamnionitis or puerperal sepsis. Treatment with antenatal corticosteroids is associated with an overall reduction in neonatal death (relative risk (RR) 0.69, 95% confidence interval (CI) 0.58 to 0.81, 18 studies, 3956 infants), RDS (RR 0.66, 95% CI 0.59 to 0.73, 21 studies, 4038 infants), cerebroventricular haemorrhage (RR 0.54, 95% CI 0.43 to 0.69, 13 studies, 2872 infants), necrotising enterocolitis (RR 0.46, 95% CI 0.29 to 0.74, eight studies, 1675 infants), respiratory support, intensive care admissions (RR 0.80, 95% CI 0.65 to 0.99, two studies, 277 infants) and systemic infections in the first 48 hours of life (RR 0.56, 95% CI 0.38 to 0.85, five studies, 1319 infants). Antenatal corticosteroid use is effective in women with premature rupture of membranes and pregnancy related hypertension syndromes.