The number of babies born too early dropped to 11.4 percent of all births in 2013, the best number in 17 years.
But that's still more than 450,000 children being born too early. Those babies face in increased risk of death, and those who survive are more likely to have problems including intellectual disability, vision or hearing loss, cerebral palsy and breathing trouble.
One reason for the success is that women, doctors and hospitals are getting the message about the benefits of waiting until labor begins, rather than choose to deliver a few weeks early.
"After 37 weeks there was a little bit of a cavalier attitude, that the baby was OK and it was OK to deliver," says Dr. Siobhan Dolan, a professor of obstetrics and gynecology at the Albert Einstein School of Medicine and a spokesperson for the March of Dimes. The nonprofit released its premature births report card Thursday, based on CDC data.
Recent data has shown that babies born at 37 weeks are still more likely to have complication and end up in the NICU. "While 37 weeks is better than 35 weeks, 39 weeks is better than 37 weeks," Dolan told Shots.
Many issues play into prematurity, including genetics and family history, preexisting medical conditions, whether a woman has delivered prematurely before and race.
Preterm births are more common among African-American women, at 16.5 percent. For Hispanic women, the number is 11.6 percent. White women and Asian women give birth prematurely about 10 percent of the time.
A national map of preterm birth rates delivers that message starkly: rates are highest in the Deep South, where African-American women are more likely to be poor and lack access to health care. Women without health insurance are twice as likely to have a premature baby.
The preterm rates also track obesity rates, Dolan notes. "Being overweight or obese is a major factor in preterm birth and lots of other health conditions," she says.
Though these new numbers hit the federal Healthy People 2020 goal for reducing premature births, the March of Dimes folks say the U.S. should aim for 9.6 percent, in line with other wealthy countries.
Medical expenses for an average premature infant are about $54,000 compared to just $4,000 for a healthy newborn.