THURSDAY, Jan. 29, 2009 (HealthDay News) -- Giving a second dose of steroids to babies still in the womb can reduce their post-birth respiratory problems and does not seem to affect their growth the way multiple courses can, new research shows.
In babies born before 34 weeks, about 43 percent of those given a second dose of steroids in utero had complications, compared with about 63 percent of the babies given a placebo.
"We saw a 31 percent reduction in overall composite neonatal morbidity. That's highly significant," said study author Dr. James Kurtzman, an associate clinical professor in the division of maternal-fetal medicine in the department of obstetrics and gynecology at the University of California, Irvine.
The real advantage, he added, came from the reduction in respiratory problems. Fewer babies had respiratory distress syndrome, and fewer babies needed mechanical ventilation.
Results of the study were to be presented Jan. 29 at the Society for Maternal-Fetal Medicine's annual meeting in Washington, D.C. The study will also be published in the March edition of the American Journal of Obstetrics and Gynecology.
Kurtzman and his colleague, Dr. Thomas Garite, began the study because they were concerned that some premature babies were missing out on the potential benefits from at least one dose of pre-birth steroids.
When doctors first started giving steroids to mothers who appeared to be going into pre-term labor, they discovered that, for the babies' health, it was best if the steroid dose was given no more than seven days before delivery.
But it's not always easy to tell exactly when a woman will deliver. So, if a woman passed the seven-day mark and still had not delivered, doctors would repeat the steroid dose. However, doctors soon learned that multiple courses of steroids led to growth restriction and smaller head circumferences in the babies.
"Then the pendulum swung the other way, and doctors were holding out on giving the first dose" until they were sure the woman was going to deliver, Kurtzman explained. That resulted in some women never getting treated before delivery.
"So, we developed this study for patients that remained pregnant for more than two weeks after receiving their first course," he said.
The study included 437 women from 18 medical facilities -- both community hospitals and academic medical centers. The women were randomly assigned to receive either a second, so-called "rescue," dose of steroids closer to delivery or a placebo.
The researchers found a significant reduction in respiratory problems for babies who received the second dose of steroids. Plus, they found no evidence of growth restriction or smaller head circumferences.
"We try to do the best we can to predict who's going to deliver early, but it's not always possible," Kurtzman said. "This information allows us to be a little bit less concerned about the timing of the first course, and that has a tremendously positive impact."
Dr. Peter Bernstein, a maternal-fetal medicine specialist at Montefiore Medical Center in New York City, said that premature birth is "one of our top problems" in obstetrics. "It's the second leading cause of neonatal mortality in the U.S.," he said. "This study shows we're continuing to chip away at this problem, and we're doing better."
The March of Dimes has advice for expectant moms on preventing premature birth.