Jan. 10, 2001 -- A generation ago, they usually died, but these days premature babies weighing as little as 1 pound at birth routinely survive and can eventually thrive. Still, they may face a host of short- and long-term medical problems, including chronic lung disease.
Approximately 30% of babies who weigh less than 2 pounds at birth will develop serious lung disease as a result of being placed on ventilators. While necessary to keep them alive, the ventilators can also cause inflammation and scarring of the tiny, underdeveloped lungs.
To reduce this inflammation and ward off lung damage, doctors often give the steroid drug dexamethasone to preemies, which previous studies have shown to be effective. Effective -- but not necessarily safe, according to the results of a new trial.
Even moderate doses of steroids are unsafe in premature babies, according to the study, which appears in tomorrow's issue of New England Journal of Medicine. In fact, the researchers ended their study early upon finding that a large number of newborns treated with dexamethasone required emergency surgery to repair holes or tears that developed in their intestines.
"We initially planned to enroll 1,200 newborns in this study, but we had to interrupt it after enrolling just 220 because of this unanticipated side effect," lead author Ann R. Stark, MD, of Boston's Brigham and Women's Hospital, tells WebMD. The complication occurred three times more often in babies given the steroid drug than in those who received a nonactive "placebo" substance, she says.
"Obviously, these babies need to be on ventilators to survive, but this is tricky when they are that small," says Susan W. Aucott, MD, medical director of the neonatal intensive care unit at Johns Hopkins Medical Center in Baltimore. "We don't know why certain babies develop chronic lung disease and others do not, but it does seem that the smaller, sicker babies are more prone to getting it. And these babies are the ones who tend to do worse in the long run."
In this study, Stark and colleagues looked at infants weighing between 1 and 2 pounds at birth that had been treated for 10 days with moderate doses of the steroid -- and then compared them with babies of a similar weight who were given a placebo treatment for the same amount of time. They found the two groups had no difference in risk of developing chronic lung disease, but 14 infants treated with the steroid developed intestinal tears requiring surgery, compared with just four infants in the placebo group.
"We also found that babies on dexamethasone didn't grow as well as those on placebo, which has been seen in other studies," Stark says. "The main point is that this agent appears to have no discernable effect on chronic lung disease in preterm infants, and its use is associated with serious complications."
"The evidence from this study and from some others suggests that using moderate-to-high doses of dexamethasone in premature newborns in the first days of life has not been beneficial and is probably harmful," says Aucott, who was not involved in the study but agreed to review it for WebMD. "But the million-dollar question remains, 'What can we do?' It has been shown that chronic lung disease is a marker for developmental problems later on. So it is possible that if we are able to [find ways to] improve chronic lung disease, we may also improve developmental outcome."