Premature birth rates continue to fall in the United States, according to a new report from the March of Dimes, but the country still has more babies born too early than any other industrialized nation in the world.
The nonprofit pregnancy organization's annual report card on premature, or preterm, births found the national rate dropped to 11.5 percent in 2012, a 15-year low, and the sixth consecutive year rates have fallen. But premature birth remains the leading cause of newborn death in the U.S., and children born too early face serious complications which could last a lifetime.
About 450,000 babies are born prematurely each year, which is defined as a birth at least three weeks before their expected due date.
Last year's report put the national preterm rate at 11.7 percent.
The U.S. preterm birth rate peaked in 2006 at 12.8 percent after a steady two-decade rise. The March of Dimes estimates that about 176,000 fewer babies were born prematurely because of improvements to the birth rate since 2006, for a cost savings of about $9 billion.
"Although we have made great progress in reducing our nation's preterm birth rate from historic highs, the U.S. still has the highest rate of preterm birth of any industrialized country. We must continue to invest in preterm birth prevention because every baby deserves a healthy start in life," March of Dimes President Dr. Jennifer L. Howse said in a statement.
The organization's goal is a 9.6 percent premature birth rate by 2020.
For the report card, researchers calculate rates of premature births and track states' individual progress in lowering those rates.
This year, six states received an "A" grade for meeting the 9.6 percent goal: Alaska, California, Maine, New Hampshire, Oregon and Vermont.
Thirty-one states saw improvements in their preterm birth rates compared to last year's report.
Three states -- Louisiana, Mississippi, Alabama -- and Puerto Rico received "F's."
The full list of grades can be found on the March of Dimes website.
Overall, the U.S. received a "C" grade from the nonprofit.
Worldwide, about 15 million premature babies are born prematurely -- that's about 1 in 10 births.
A Nov. 2012 study from the March of Dimes and other groups including the World Health Organization, Save the Children and U.S. National Institutes of Health, found that f
- Nearly eliminating induced labors and C-sections scheduled ahead of due dates unless they're medically necessary
- Helping women quit smoking.
- Using just one embryo, not multiples, in vitro fertilization.
- Providing regular injections of the hormone progesterone to certain women at high risk, largely because of a prior preterm birth.
- Putting a stitch into the cervix of certain high-risk women, those who have what's called a short cervix.
The new report touted progress from states at reducing contributing factors linked to premature births. Thirty-seven states and the District of Columbia reduced the number of uninsured women of childbearing age, while 35 states and the District reduced the number of women smokers.
Risk factors for preterm birth include previously having a child born prematurely, obesity, diabetes, high blood pressure, smoking, mom's age (either under 17 or over 40), and pregnancies spaced too closely together.
Babies born prematurely face short-term health risks for breathing problems, heart conditions, brain bleeding, problems with controlling body temperature, digestive issues, anemia, jaundice, problems with metabolism and increased risk for infection from a weaker immune system, the Mayo Clinic points out. Long-term, premature birth is linked to cerebral palsy, cognitive difficulties, behavioral and psychological problems, problems with hearing and vision and other chronic health issues.