The U.S. infant mortality rate fell just a little bit in 2010, federal health researchers reported Wednesday. They report that the U.S. infant mortality rate was 6.14 infant deaths per 1,000 births in 2010, which is just 4 percent lower than the rate of 6.39 in 2009. This adds up to 24,572 babies who died at or around birth in 2010. Also, babies born at 37 to 38 weeks of gestation were 62 percent more likely to die than those born at 39 to 41 weeks, the report finds. And 12 percent of all U.S. babies born in 2010 were pre-term. The rate is viewed as an important measure of a country’s overall health. Birth defects and low birth weight were the two leading causes of newborn death, the survey by the National Center for Health Statistics found. And babies born to teenage mothers were the most likely to weigh too little, the NCHS, part of the Centers for Disease Control and Prevention, said. The United States may be one of the richest countries in the world, but has a very high rate of infant mortality compared to other wealthy countries.