There were slightly fewer than 5.4 infant deaths per 1,000 live births in 2025, according to the Centers for Disease Control and Prevention.

While that appears to be a small decline from about 5.5 in 2024 and 5.6 in the two years preceding, researchers say it is statistically meaningful and translates to hundreds of fewer infant deaths per year.

It’s difficult to pinpoint what’s driving the recent developments, but “this is an encouraging data point, and we hope that this trend will continue,” said Dr. Michael Warren, chief medical and health officer for the March of Dimes.

Infant mortality is the measure of how many babies die before reaching their first birthday. Because the number of babies born in the U.S. varies year to year, researchers calculate rates to compare infant mortality over time.

The overall numbers, too, have been going down. U.S. infant deaths fell to about 19,350 last year, according to provisional CDC data that may rise a little as additional analysis is completed. The final tally is still expected to be down from about 20,050 in 2024 and about 20,160 in 2023, according to the agency.

The U.S. rate has inched down over the decades — it was at 7.5 per 1,000 three decades ago — thanks to medical advances and public health efforts.

But it has remained worse than other high-income countries, which experts have attributed to poverty, inadequate prenatal care and other problems. A study published last year found the U.S. infant mortality rate in 2022 — when the rate rose — was nearly twice as high as what was seen in several other high-income democratic nations, including Italy, Japan, Spain and Sweden.

That was the year of the first statistically significant jump in the U.S. rate in about two decades. Experts attributed that rise to a rebound in RSV and flu infections.

In 2023, U.S. health officials began recommending two new measures to prevent the toll on infants: one was a lab-made antibody shot for infants that helps the immune system fight off the virus, and the other was giving an RSV vaccine to women between 32 weeks and 36 weeks of pregnancy. A March of Dimes expert last year said the effort likely contributed to the improvement in 2024.

Meanwhile, a decline in sudden infant death syndrome could be connected to an increase in education around safe sleeping for infants, Warren said in a statement.

The CDC posted the 2025 provisional data in late May. On Tuesday, the agency released a more in-depth analysis of 2024 infant mortality data, offering details not yet available for 2025. Among that report’s highlights:

— Death rates declined both for the youngest infants, less than 28 days old, and for older infants. Those declines continued last year, the 2025 provisional data indicate.

— In 2024, infant mortality continued to differ by race, sometimes dramatically. Death rates for infants born to Black women were more than twice as high as those for the infants of Hispanic, white and Asian American women.

— Researchers noted a decline in the mortality rate for infants born at full term, at 39 to 40 weeks. But rates did not change significantly for other gestational age groups.

— Mississippi had the highest infant mortality rate, at 9.65 deaths per 1,000 births, and New Hampshire had the lowest, at just under 3 per 1,000.

“These differences are reflective of a variety of reasons related to access to care, community factors, and policies that improve health and outcomes,” Warren said.

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