

Sgt. Eric Ziegenmeyer and his wife, Jennifer, hold their twin sons, Brian, left, and Benjamin, dressed in football jerseys for a Halloween party at the Children's Hospital at Memorial Hospital Central in Colorado Springs, Colo. The two boys, born 11 weeks premature, are expected to be in the NICU for 4-6 more weeks. (AP Photo/The Colorado Springs Gazette/Jerilee Bennett)

The preterm birth rate - that is, the percentage of infants born before 37 weeks gestation - fell to its lowest level in 17 years, according to the CDC. As the March of Dimes notes in its latest Premature Birth Report Card, that means the U.S. hit the federal Healthy People 2020 goal for preterm births seven years early.

But there's still plenty of work to be done. The March of Dimes has set a more aggressive goal of reducing the preterm birth rate to 9.6 percent by 2020, and gives the U.S. a "C" grade overall for its reduction efforts.

"The U.S. still has one of the highest rates of preterm birth of any high-resource country and we must change that," said March of Dimes President Dr. Jennifer L. Howse in a statement. In 2010, the U.S. ranked 131st out of 184 countries on preterm birth rate, according to a report by the World Health Organization. In that year our premature birth rate was the same as Somalia's.

Why the relatively high rate? One factor is insurance: the rate of preterm birth among uninsured women stands at 19.8 percent. To the extent that Obamacare allows more Americans to get health insurance, it will have the effect of reducing preterm births.

Another factor is that more women have been electing to have births by c-section earlier in their pregnancy terms, although the March of Dimes notes that that trend seems to be reversing.

Some states are doing a better job of reducing preterm births than others. Vermont, New Hampshire, Maine, Oregon and California all had premature birth rates at or below the March of Dimes' 9.6 percent target, earning them an "A" grade in their report card. On the other hand, Louisiana, Alabama and Mississippi all had rates above 14.6 percent, earning them an "F." In Mississippi, nearly a quarter of births to uninsured mothers were premature.

Going forward, the March of Dimes is focusing on three strategies to reduce the rate even further: reduce the number of uninsured women, reduce the number of late-preterm births (those between 37 and 39 weeks), and reduce the incidence of smoking during pregnancy, which is linked to premature birth.

Aside from the public health concerns, there's also a strong financial impetus behind these reforms: "Medical expenses for an average premature infant are about $54,000 compared to just $4,000 for a healthy newborn," the March of Dimes reports.