For infants born at 32–36 weeks of gestation (the preterm
category where most preterm births occur), the U.S. infant mortality rate was second highest among 11 countries; only Poland had a higher rate. However, for infants born at 37 weeks of gestation or more, the U.S. infant mortality rate was highest among the countries studied (2.20 per 1,000), and about twice the rates for Denmark, Finland, Norway, Sweden, and Switzerland.