Late preterm birth rates have risen among mothers of all ages from 1990 to 2006, including teenage mothers (up 5 percent). Among mothers age 25 years and over, late preterm birth rates increased by more than 20 percent from 1990 to 2006. Younger (under age 20 years) and older (40 years and over) mothers are the most likely to have a late preterm baby.
For more trends in late preterm births in the United States, visit the NCHS Data Brief at http://www.cdc.gov/nchs/data/databriefs/db24.pdf.
NCHStats 
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