Newly released federal data has found that preterm births in the U.S. have risen significantly in recent years, according to a report from the Centers for Disease Control and Prevention (CDC). The rate of preterm births rose by 12 percent nationally between 2014 and 2022, posing a concerning trend that has left doctors puzzled.

Manisha Gandhi, chair of the American College of Obstetricians and Gynecologists Clinical Practice Guidelines Committee, highlighted several potential contributing factors. She mentioned the increase in patients with obesity, higher risks for hypertension or preeclampsia, and more cases of diabetes. These risk factors may lead to earlier delivery and could be playing a role in the rise of preterm births.

Environmental factors such as exposure to hormone-disrupting chemicals and air pollution are also believed to be contributing to the increase in preterm births. Leonardo Trasande, head of New York University’s Center for Environmental Hazards, pointed out that microplastic exposure, including from the air, may be involved. He referenced a 2016 study that estimated about 3 percent of preterm births could be attributed to exposure to particles making up air pollution, with an increasing amount of those particles being from plastics.

Preterm births, defined as those occurring before 37 weeks of pregnancy, account for approximately 1 in 10 births in the U.S., according to the March of Dimes. The health effects of premature births on infants become more severe the earlier an infant is born, leading to potential developmental delays, asthma, or neurological conditions.