Despite being one of the most advanced countries in the study of science and medicine, the United States has an unusually high preterm birthrate of about 12 percent. Preterm births can pose a number of health threats to a baby, including accountability for 35 percent of all infant deaths in 2010.

But what are the underlying causes of these surprising statistics?

Nearly 20 percent of preterm births occur in newborns whose mothers may not be receiving the treatment they need. In addition, smoking, obesity, and age can contribute to an increased risk of preterm births. One-third of Americans remain obese and a large percentage of women giving birth to their first child later in life, creating an additional risk to newborns.