TUESDAY, Nov. 1, 2011 (HealthDay News) -- The rate of preterm births in the United States dropped slightly, to 12.2 percent in 2009, from its high three years earlier, according to a new analysis by the March of Dimes.
But those numbers fall far short of the March of Dimes' goal of 9.6 percent by 2020, explained Dr. Jennifer Howse, president of the March of Dimes.
"Things are getting a little bit better. We're excited to report progress for three years in a row," said Howse. "Our rate of preterm birth is just too high though."
Vermont, which already has a 9.3 percent rate, was the only state to earn an "A" on the March of Dimes 2011 Premature Birth Report Card.
Grades were arrived at by comparing a state's preterm birth rate to the 2020 goal.
Nationwide, the new figures represent a decline of almost 5 percent from 2006, when the preterm rate peaked at 12.8 percent of all live deliveries. The improvement resulted in savings of at least $2 billion in health care and related costs, the organization said.
Any birth that occurs before 37 weeks of gestation is considered preterm, according to the U.S. Centers for Disease Control and Prevention (CDC). It's the leading cause of death in newborns, and can cause serious health problems in those who survive. Babies born prematurely may have lifelong intellectual disabilities, breathing problems, cerebral palsy, digestive problems, and vision and hearing loss, reports the CDC.
Risk factors for having a preterm birth include having a chronic illness, such as obesity, high blood pressure or diabetes, smoking or illicit drug use during pregnancy, certain infections, and carrying more than one baby (twins or more), according to the CDC. A previous preterm birth also raises the odds, but preterm birth can also occur in women who have none of these risk factors.
Overall, the United States earned a "C" on the new report card, released Nov. 1. Alabama, Mississippi, Louisiana and Puerto Rico received an "F". Eleven states (mostly in the South) and the District of Columbia scored a "D". Nineteen states earned a "C", and 16 earned a "B".
Howse said at least four factors have had an impact on the premature birth rate. One is that a new treatment to help prevent preterm birth -- progesterone injections -- was approved by the U.S. Food and Drug Administration to treat women who've already had a preterm birth. Another important reason for the decline is that fewer women smoke during pregnancy. The rate of smoking went from 19.6 percent to 17.6 percent of women of childbearing age, according to the report card.
The third factor is that fewer elective labor inductions and cesarean-sections are performed before 39 weeks' gestation, and the fourth reason is a slight improvement in the percentage of women getting into prenatal care early, according to Howse.
"I think where we're really seeing a reduction is in the late preterm births. There's been more and more evidence on not doing elective deliveries before 39 weeks," said Dr. Deborah Campbell, director, division of neonatology at Montefiore Medical Center in New York City.
Howse said what's not as clear-cut is how to make inroads for the half of all preterm births that don't have known causes. "We have to study the problem and develop interventions," she said.
The report card also showed some significant geographic differences in the rates of preterm birth, with higher rates occurring in the Southern states. Howse said that certain risk factors may be present in the Southern states, such as obesity and smoking.
Overall, however, "We are on the road to success," she said. "This trend has held for three years in a row, and epidemiologists would be willing to call that a trend." But a half-million infants are still being born too soon in the United States, she said.
The take-away message from this report card is that "it's important to plan your pregnancy," Campbell said. "Over 50 percent of pregnancies in the U.S. are unplanned. There still needs to be a lot of education and outreach to make sure women are getting folic acid before and during pregnancy and that they're in good health at the time they conceive."
More information
Read more about birth defects and how to prevent them from the March of Dimes.
