Sudden unexpected infant death is rising again in the United States, and a study published September 22, 2026, in JAMA Network Open found the rise is sharpest among babies born to Black mothers.
The study looked at federal records covering nearly 58 million live births between 2003 and 2024, matching birth certificates to death certificates. Across those years there were 366,384 infant deaths among babies born to non-Hispanic Black mothers and 224,733 among babies born to non Hispanic white mothers.
Leslie Root, a demographer and assistant research professor at the Institute of Behavioral Science at the University of Colorado Boulder, is a co-author.
The number that should change what gets worked on is this one. Sudden unexpected infant death, which researchers shorten to SUID, now accounts for more than a third of the gap between Black and white infant mortality. That makes it the single largest contributor to the gap. Preterm birth still accounts for most of the overall difference, but SUID is the piece that has been growing.
Infant mortality for babies born to Black mothers is about twice the rate for babies born to white mothers, and that gap has widened since 2020. The rise in SUID began alongside the pandemic. The authors point to off season respiratory infections and to pandemic era social and economic strain as possible contributors, and they note a rise in opioid deaths among Black Americans over the same period. About 3,400 infants in the United States die unexpectedly every year.
What that means in practice is where the attention goes next. For years the work on this gap has concentrated on preterm birth, and for good reason. This study says that if the preterm birth gap closed tomorrow, a wide gap would remain, and the largest remaining piece of it would be babies dying suddenly in their first year of life.
The study did not include Native American and Alaska Native populations. The authors say future work may look at parental opioid use.
