Senate passes bill to help prevent premature births

"Preterm birth rates have now dropped for five consecutive years after rising steadily for three decades. The PREEMIE Reauthorization Act will continue to fuel our progress by supporting federal research and promoting known interventions and community initiatives."

The bill authorizes research on preterm births at several agencies as well as a campaign to promote healthy pregnancies.

The March of Dimes reported this week that 11.7 percent of U.S. infants were born prematurely in 2011, the lowest rate in a decade. The figure still earned the United States a "C" grade.

Globally, the highest rates of pre-term births are in Africa, with an 18.1 percent rate in Malawi, according to the World Health Organization. The lowest rate is in Belarus, at 4.1 percent.

An infant is classified as premature when born alive before 37 weeks of pregnancy.