Glucocorticoid drugs that are used to treat chronic lung damage in preemies proved harmful for brain in mice.  Researchers from Washington University School of Medicine in St. Louis say that the drugs seem to cause cognitive and motor control problems even if they are given before birth.

In their study, the researchers observed the effects of the synthetic glucocorticoids dexamethasone and betamethasone that were given to preemies to help lung development. These drugs seemed to cause brain cell death in mice when given four and ten days after birth.

Kevin K. Noguchi, who is one of study authors, says in a university news release: “The drugs seemed to damage neural progenitor cells that are responsible for producing new neurons.  So it’s quite easy to understand that if the cells that produce new neurons are killed, it can cause severe neurodevelopmental effects.”

Dr. Nuri B. Farber, who is an associate professor of psychiatry, says in a news release: “There are detrimental effects on cognitive function in non-motor regions of the brain, as the cerebellum connects to other brain structures. Some other studies have already shown IQ declines in children who received these drugs earlier in life and this new study may help to find why this happens.”

The study is expected to be presented at the Society for Neuroscience annual meeting, in Washington, D.C. on Monday.