THURSDAY, Nov. 19 (HealthDay News) -- The number of infants born "late preterm," or between 34 and 36 weeks of pregnancy, rose by 20 percent in the United States between 1990 and 2006, according to the November issue of the U.S. Centers for Disease Control and Prevention's National Center for Health Statistics Data Brief.
Joyce A. Martin, of the National Center for Health Statistics in Hyattsville, Md., and colleagues analyzed data from the Natality Data File from the National Vital Statistics System, which includes information for all births occurring in the United States.
The researchers found that the rate of late preterm births increased 20 percent from 1990 to 2006, from 6.8 to 8.1 percent of births. The increases occurred among mothers of all ages, among non-Hispanic white and Hispanic mothers, and in all states (but not the District of Columbia). The percentage of late preterm births in which labor was induced increased from 7.5 to 17.3 percent, and the percentage of late preterm births where delivery occurred by cesarean section increased from 23.5 to 34.3 percent.
"The number and rate of babies born just one to three weeks short of 'term' has risen substantially in recent years," Martin and colleagues conclude. "The rise in late preterm births is important because these infants are developmentally and physiologically immature and suffer more health complications and have higher death rates than infants born at term."
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