Preterm births - United States, 2007.

Preterm infants (those born at <37 completed weeks of gestation) are less likely to survive to their first birthday than infants delivered at higher gestational ages, and those who do survive, especially those born at the earlier end of the preterm spectrum, are more likely to suffer long-term disabilities than infants born at term. During 1981--2006, the U.S. preterm birth rate increased >30%, from 9.4% to 12.8% of all live births. Although lower during 2007 and 2008, the U.S. preterm birth rate remains higher than any year during 1981--2002.