Sudden unexpected infant deaths surged among Black babies in 2020

Sudden unexpected infant deaths, or SUIDs, include SIDS and other unknown causes.

(CNN)Each year, thousands of babies die suddenly and unexpectedly, and more than 3,300 young lives were lost in 2020. Rates remained stubbornly high in the first year of the Covid-19 pandemic, even as overall infant mortality dropped to a record low.

A study published Monday in the journal Pediatrics found that the rate for Black babies spiked in particular, widening an already stark disparity.
About 1 out of every 6 infant deaths were considered sudden unexpected infant deaths, or SUIDs, a broad classification of deaths that includes sudden infant death syndrome, known as SIDS, along with accidental suffocation and strangulation in bed and other unknown causes.
    While the SUID rate for White babies dropped to the lowest it has been since 2017, the rate for Black babies in 2020 was the highest it has been since then. Rates that were already about two times higher for Black babies in 2017 grew to nearly three times higher in 2020, the study found.
      Sharyn Parks Brown, an epidemiologist with the US Centers for Disease Control and Prevention's Division of Reproductive Health and co-author of the study, said the research team reanalyzed the data a couple of times to be sure they were interpreting the findings correctly.
        For decades, SUID rates had stayed consistent within each racial and ethnic group and were always highest among American Indian infants. But in 2020, the rate among Black infants surpassed that of American Indian infants.
        "We would typically -- ideally -- look at five years of data in order to see any sort of trend emerging. So, these are very preliminary findings," Parks Brown said. "But this is something that we're going to have to continue monitoring."
          In a commentary responding to the research, physicians said that the high rates of sudden unexpected infant deaths in the United States -- and growing disparities -- "reflect our societal failures."
          Socioeconomic disparities "not only result in limited access to health care and education, but also in many families not having a stable, safe place for their infants to sleep," they wrote.

          Untangling underlying causes

          In 2020, 41% of all sudden unexpected infant deaths were attributed specifically to SIDS, 27% were identified to be accidental suffocation and strangulation in bed, and 31% were classified as an unknown cause.
          Deaths attributed specifically to SIDS jumped between 2019 and 2020, rising from the fourth leading cause of infant mortality to the third.
          But this particular trend might highlight just how much we don't know about these deaths, the new study suggests.
          The lines between the three classifications within the SUID category are blurry, and the proportions have shifted over the years. Experts say there's been wide variation in how medical examiners and coroners code them, and they're less distinct than they may seem.
          "The root causes of, and distinction between, SIDS and an unknown cause of death are poorly defined," said Cheryl L. Clark, associate director of epidemiology, evaluation and metrics at the Association of Maternal and Child Health Programs, who was not involved in the new study.
          Individuals responsible for death certification have convened for a couple key meetings in recent years with specific intent to find consistency in the practice. And according to the new study, the unexpected increase in SIDS deaths in 2020 is most likely a result of shifting diagnostic criteria.
          While the SIDS rate increased about 15% from 2019 to 2020, the broader SUID rate -- which also includes deaths attributed to accidental suffocation and other unknown causes -- increased only 3% in that year, an increase that's not considered statistically significant, the researchers found.
          Still, the latest data emphasizes why continued focus -- and better understanding -- of the topic is important.