After holding steady from 2000 through 2005, the US infant mortality rate dropped 12% from 2005 through 2011, according to a new CDC report. In 2011, the rate was 6.05 deaths of babies less than a year old for every 1,000 births, down from 6.87 in 2000. Premature births also have been dropping since 2006, and many hospitals and other organizations have been working to prevent mothers from scheduling deliveries before 39 weeks without a valid medical reason. Researchers say both those factors likely contributed to the drop in the infant mortality rate, the New York Times reports.