On the March of Dimes’ new report card for preterm birth rates, the U.S. overall scores a D+

In the U.S. overall, 10.5% of births are preterm.

A (<= 8.1%)
B (8.2-9.2%)
C (9.3-10.3%)
D (10.4-11.4%)
F (>=11.5%)

Notes

Preterm is less than 37 completed weeks of gestation, based on obstetric estimate of gestational age. Puerto Rico is not included in the United States total grade.