Researchers find that drugs that reduce infant mortality could lead to long-term health problems

The research, published in The BMJ on August 2 analyzed data from 1.6 million babies and found that about 40 percent of babies with early corticosteroid exposure — defined as exposure at 34 weeks’ gestation or earlier — were born at term. The full-term babies had an increased risk of both short- and long-term health problems, including admission to the neonatal intensive care unit, breathing and growth problems and an adverse neurological outcome, the researchers found.

Corticosteroids are used to increase the chances of survival of very premature babies and reduce health problems. However, the effects on long-term child health are not well understood, especially in infants who exceed expectations and are born on term. The research shows that many babies exposed to steroids avoid preterm birth, but new risks arise for other future health complications.

“Preterm birth is very difficult to predict; we need better prediction models to prevent overexposure to interventions such as steroids because there is a potential risk,” said Sarah McDonald, senior author of the study and professor in the Department of Obstetrics and Gynecology at the McMaster University.

To conduct the study, researchers conducted a systematic review and meta-analysis of data from seven randomized controlled trials and ten population-based studies involving 1.6 million babies born since 2000.

More than half of infants exposed early to corticosteroids were born together at term (37 weeks or longer) and late preterm (34-36 weeks), and researchers found similar results in this combined group. For very preterm infants, antenatal steroids can potentially save lives and reduce serious morbidity, but as pregnancy progresses, the benefits shift to risks.

“Antenatal steroids are a double-edged sword: highly beneficial for babies born very preterm, and potentially harmful for babies born at term,” says McDonald, Canada Research Chair in Maternal and Child Disease Prevention and Intervention.

The authors say more research with long-term follow-up in randomized controlled trials is crucial. They also warn against a less liberal approach to steroid use during pregnancy.

The study was supported by the Canada Research Chairs program.