The U.S. has received a "D+" for preterm birth rates for the third year in a row, with no substantial change in those rates, according to a Nov. 14 March of Dimes report.
Preterm babies are those born at 37 weeks' gestation or earlier; these children have a higher risk for physical and intellectual disabilities. Last year, 370,000 babies were preemies.
Here are five things to know:
1. In 2023, the preterm birth rate was 10.4%, remaining at a historical high. In 2013, it was 9.8%.
2. One-third of the country's largest cities received an "F" grade for preterm birth rates.
3. External factors may contribute to the elevated preterm birth rates. More than 40% of pregnant people were exposed to extreme heat and nearly 75% lived in areas with poor air quality.
4. Inadequate prenatal care and maternal health also contributed. In 2013, the rate of inadequate prenatal care rose 15.7%, the highest in a decade. Inadequate care is associated with a 9% increase in the rate of preterm births. Women with diabetes had a preterm birth rate of 28.8% and women with high blood pressure had a rate of 23.3%.
5. Twenty-four states had worse ratings this year. Many of the states with the highest rate of preterm births were in the South: Alabama, Arkansas, Georgia, Louisiana, Mississippi and South Carolina.