Steroids Affect Brain Development in Premature Babies

Smaller cerebellum seen in preemies who receive glucocorticoids

October 24, 2011

Steroids impact the brains of infants who receive them shortly after birth.

Premature babies routinely get powerful steroids both before and after they are born. The drugs help the babies' tiny lungs mature and boost blood pressure, among other benefits. Previous research in animals found the drugs can affect brain development. Now, a new study confirms similar effects in human babies.

Caring for premature babies requires a careful balancing act. On the one hand, preemies are at risk for a variety of medical problems. But their tiny, developing bodies are ultra sensitive to side effects from important medicines they may need.

Researcher Emily Tam, MD, of the University of California-San Francisco explains that animal studies found that the steroids called glucocorticoids affect a certain part of the brain.

"The cerebellum is particularly targeted, resulting in cell death and decreased cell growth," Tam says. "And so, the question then is, is this same thing happening in humans?"

The cerebellum is involved in motor control and some cognitive functions, among other things, so it plays a critical role in an infant's first years.

In a study, which was published in Science Translational Medicine, 172 premature babies born in the United States and Canada got MRI scans to measure their cerebellums. Tam says researchers found no adverse affects from steroids given to the pregnant mothers before birth.