A few years ago, a study published by the World Health Organization estimated that, globally, 10 percent of babies were born prematurely.

Crump says the findings of his study underscore the need to reduce the number of preterm births.

"It's extremely important for pregnant women to have regular prenatal care to reduce their risk of delivering preterm. And also, for survivors of preterm births to avoid other risk factors for disease, like smoking or obesity, in order to offset the increased risk that we found."