A course of antenatal corticosteroids can reduce mortality by about half in neonates born before 24 weeks, according to findings from a recent meta-analysis.

Previous studies have established that antenatal corticosteroids, used to hasten development of the lungs and therefore improve chances of survival, are helpful when given to women at high risk of preterm delivery between 24 and 34 weeks of gestation. However, little evidence has been available to recommend their use when risk of preterm delivery became evident before 24 weeks.

In the current meta-analysis, Christina Park, of McMaster University in Hamilton, Ontario, and her colleagues, reviewed data from observational studies published between 2002 and 2011 that included more than 3,600 neonates born before 24 weeks ( Obstet Gynecol. 2016 Mar 7;127:715-25 ).

The researchers found that the odds of in-hospital mortality – the primary outcome of the study – were 52% less in those neonates that had been treated with antenatal corticosteroids (58.1% compared with 71.8%; adjusted odds ratio, 0.48), a difference that reached statistical significance. They graded the evidence in these studies as being of “moderate” quality.

A subgroup analysis comparing outcomes for neonates at 22 and 23 weeks of gestation found no difference in terms of in-hospital mortality.

Secondary outcomes such as respiratory distress syndrome and other diseases associated with preterm birth did not reach statistical significance. This finding was surprising, the researchers noted, because they had expected a reduction in morbidities would accompany lowered mortality. However, a misdiagnosis of respiratory distress syndrome may have occurred in the included studies, they wrote.

Antenatal corticosteroids may help reduce mortality in neonates delivered before 24 weeks and clinicians should consider them for women at this gestational point who would choose postnatal resuscitation. “Family counseling and planning of services are essential for these births,” they wrote, “because advances in care have opened the possibility of survival at progressively early gestations.”

Two of the researchers reported receiving grants from the Canadian Institutes of Health. They reported having no other financial disclosures.