Michelle Healy, USA TODAY
For the fifth consecutive year, the preterm birthrate in the USA continued its slow but steady downward trend, good enough to earn a "C" on a new March of Dimes report card.
The nation's premature birthrate is 11.7% of all live births - the lowest in a decade, according to figures from the National Center for Health Statistics. The March of Dimes has set a goal of 9.6% by 2020.
"We're on the right track," having reversed a trend that included increases every year for decades," says Jennifer Howse, president of the non-profit pregnancy and baby health group. Its 9.6% goal reflects the adoption of measures such as getting mothers to stop smoking and providing access to prenatal care.
MORE: Report card on premature births
In 2006, the nation's preterm birthrate peaked at 12.8% after rising steadily for more than two decades. Preterm birth (before 37 weeks of completed pregnancy) is the leading cause of infant death during the first month of life.
Having 64,000 fewer preterm babies born from 2006 to 2010 resulted in healthier babies as well as a potential savings of roughly $3 billion in health care and economic costs, the report says.
Key signs of improvement in this year's report:
-- Four states (Vermont, Oregon, New Hampshire and Maine) earned an "A" for meeting the 9.6% goal; in 2010, only Vermont earned the top grade.
-- 45 states, the District of Columbia and Puerto Rico posted improved preterm birthrates from 2009 to 2011, earning 16 of them better grades.
--The states with the highest preterm birthrates - Mississippi (16.9%), Louisiana (15.6%), Alabama (14.9%) - are among 48 states, along with Puerto Rico (17.5%) and the District of Columbia (13.7%) that have all formally set goals to lower their preterm rates 8% by 2014 from their 2009 rates.
Although the preterm birthrate "is not good enough yet," Howse says, "there now is genuine national momentum and leadership to just stay at it until we get the job done."
Key factors that continue to drive the rate of premature births in the USA include maternal smoking, insufficient access to prenatal health care services and late preterm births (infants born between 34 and 36 weeks of gestation).
Though late preterm babies are usually healthier than babies born earlier, they are three times more likely to die in the first year of life than full-term infants, the March of Dimes says. About 8% of deliveries are late-preterm, sometimes the result of medically unnecessary elective inductions and Cesarean sections.
"It's very, very important to try to support pregnancies so babies can be born as close to 39/40 weeks as possible," says pediatrics professor Deborah Campbell, director of Neonatology at Montefiore Medical Center in New York.
Just because a baby makes it to 37/38 weeks, "what we call full term," doesn't mean that they are fully developed, Campbell says. "These babies are more likely to end up in the NICU (Neonatal Intensive Care Unit), more likely to have acute health issues, and now we're finding, more likely to have issues as they reach school age."
"Babies need those extra weeks for full development of the brain and lungs," Howse says, adding that unless it is a medical necessity, women should wait until at least 39 weeks to schedule an induced labor or C-section.
Worldwide, 15 million babies are born too soon each year and more than 1 million of those infants die as a result. The USA ranked 131 out of 184 countries in premature births according to a May 2012 report by the March of Dimes, Save The Children and others.