WEDNESDAY, Sept. 19, 2007 (HealthDay News) -- Children exposed to repeated doses of steroids in-utero had no additional growth or neurodevelopmental problems up to three years after birth, two new studies found.
However, one of the studies did find a slight, though not statistically significant, increase in the incidence of cerebral palsy.
"In our study, the babies with the highest number of repeated steroid injections -- five or more -- we found a non-significant but an increased risk of possible cerebral palsy," said Dr. Ronald Wapner, director of maternal-fetal medicine at Columbia University in New York City.
That doesn't mean women should forgo corticosteroid injections if they're at risk for preterm labor, but repeated doses should be used judiciously, Wapner advised.
"One of the major advances in the health of the preterm neonate has come from giving the mother an injection of steroids to accelerate the maturation of the baby's lungs," he said. "But, the effects of that shot don't last forever. The best guess is probably about seven days."
Because the benefits of the shot don't appear to last more than a week, many obstetricians started giving women at risk of delivering early repeated injections each week until they delivered. "It became a trend in this country, and women get course after course of steroids," Wapner said.
But, he added, no one knew for sure what the exact benefits and hazards of those repeated doses might be.
The two studies -- one in the United States and one in Australia -- were designed to answer those questions. And, in fact, they did find significant benefits from repeated corticosteroid injections.
"Babies with repeated doses needed less mechanical ventilation and had a decreased incidence of lung problems. However, those benefits came at a price," explained Wapner, who said that babies who received the most steroids were smaller on average.
The two studies, published in the Sept. 20 issue of the New England Journal of Medicine, were carried out to assess if there were any longer-term effects from the repeated steroid injections.
The Australian study included 1,047 two-year olds -- 521 had been exposed to repeated steroid injections before birth and 526 were exposed to a placebo. Mothers who were given repeated steroid injections in this study received an initial course of corticosteroids followed by a weekly 11.4 milligram injection each week the mother was considered at-risk for preterm delivery or until 32 weeks of gestation.
Rates of major disability-free survival were 84.4 percent in the steroid group and 81 percent in the placebo group. At two years, there were no longer any statistically significant differences in size. There were also no differences in blood pressure, use of health services or child behavior scores.
In Wapner's study, which was supported by grants from the National Institute of Child Health and Human Development, the researchers included 486 children between the ages of 2 and 3 years old who had either received repeated steroids in-utero or a placebo. In this study, the repeat doses of corticosteroids were higher than in the Australian study. The injections included 12 milligrams of steroids given twice weekly for as long as the women were at-risk of preterm labor.
The researchers found no significant differences in growth or in neurodevelopmental outcomes. But, six children in the repeated steroid group had cerebral palsy, compared to just one in the placebo group.
There was no finding of additional cerebral palsy in the Australian study.
Dr. Alan Stiles, a neonatologist and professor and chairman of pediatrics at the University of North Carolina at Chapel Hill, said, "I don't think the question [of whether or not the steroids caused the additional cases of cerebral palsy] can be answered yet. But, there's a trend that's worrisome."
Stiles, who wrote an accompanying editorial in the same issue of the journal, said it's possible the different findings on cerebral palsy might be related to the differences in the steroid dose, but that doctors have no way of knowing for sure yet if that's the case.
"I believe that multi-dose steroids are not a terrible thing to do. These studies provide some reassurance that multi-dose steroids can be beneficial to preterm babies, but they should be viewed as a tool to be used selectively, and with careful information given to the families so that they understand the potential benefits and risks," Stiles said.
To learn more about the types of medications used in preterm labor, visit the March of Dimes.