Preterm birth risk revised upward

Published October 2, 2006

ATLANTA - Scientists now say a third of infant deaths are due to premature births - a much larger percentage than previously thought.

In the past, "preterm birth" has been listed as the cause of death in fewer than 20 percent of newborn fatalities. But that number should be 34 percent or more, said researchers at the U.S. Centers for Disease Control and Prevention.

That's because at least a dozen causes of newborn death are actually problems that go hand in hand with premature births, such as respiratory distress syndrome caused by underdeveloped lungs.

"This brings preterm birth, as a cause of death, to the kind of level that we think it deserves," said Dr. Bill Callaghan, the lead author of the study appearing today in the journal Pediatrics.

The revised statistic may lead to greater efforts to counsel pregnant women about taking care of themselves and avoiding actions, such as smoking and drug use, that can lead to preterm births.

It also may help organizations lobbying for more research into why some women who follow medical advice still have preterm babies.

At issue is how to label the causes of deaths for infants who die before they reach their first birthday.

"Preterm birth" generally describes infants who are born before 37 weeks gestation, and the term is also used as an official cause of death. Two-thirds of infant deaths occur in children who were preterm, but their cause of death is often attributed to one of the several specific problems that can occur in preterm babies.

Callaghan and other researchers reviewed about 28,000 U.S. infants that occurred in 2002.

More than 4,600 of those - or 17 percent - were attributed only to preterm birth. But the researchers also grouped in about 5,000 other deaths that were attributed to preterm-related conditions.

The researchers believe that figure is conservative and likely underestimates the true picture.