For decades, the number of American babies born too small was on the decline. But new data suggests the rate may be ticking up again—especially among African Americans.

The World Health Organization defines an underweight newborn as weighing less than 5 pounds, 8 ounces. In 2016, according to new joint report from the Robert Wood Johnson Foundation and the University of Wisconsin Population Health Institute’s annual county health rankings, 8.2 percent of new babies failed to exceed the threshold. That’s a 2 percent increase in underweight births since 2014. (The United States also fares poorly compared with other nations. See this Brookings Institution chart, based on 2011 data.)

Babies can be born too small for a number of reasons: Most commonly, it’s because they are premature or because the mother’s placenta isn’t providing enough nutrients. Low birth weight is associated with a range of health problems, from infections and brain bleeds in infancy to a higher risk of obesity, diabetes, and heart disease later in life. Birth weights are a good general indicator of the health of a community, […]