Sudden unexpected infant death claimed the lives of about 3,400 babies in the United States in 2024. Despite decades of public health work to encourage safer sleep, these deaths remain a major cause of mortality during infancy.

A new report from the US Centers for Disease Control and Prevention examined 4,861 cases that occurred between 2020 and 2024. The cases came from 31 jurisdictions participating in a registry that provides details not available from death certificates alone.

Investigators classified 73% of the deaths as involving unsafe sleep factors. Because individual cases could involve several hazards, the report’s categories overlapped.

Soft bedding was involved in 78% of the deaths, while 75% occurred on a surface other than a crib or bassinet. Another 59% involved sharing a sleep surface with a person or animal, and 46% involved infants found on their stomach or side instead of their back.

The report also documented substantial racial disparities. Black infants accounted for 38% of deaths in the registry, while the CDC noted that sudden unexpected infant death disproportionately affects Black and American Indian or Alaska Native infants.

CNN wellness expert Dr. Leana Wen said the reasons for those disparities are complex. They can include differences in access to the resources families need to implement safe sleep practices consistently.

Sudden unexpected infant death is a broad term covering the sudden death of a baby younger than 1 year. It includes sudden infant death syndrome, accidental suffocation and strangulation in bed, and deaths for which the cause remains unknown.

The American Academy of Pediatrics recommends placing babies on their backs for every sleep, including naps. Babies should sleep on a firm, flat surface designed for infant sleep, such as a crib, bassinet or portable crib that meets current federal safety standards.

That sleep space should contain a firm mattress and fitted sheet, but no pillows, blankets, quilts, bumper pads or other soft objects. Parents worried about warmth can use a wearable blanket or well fitting sleep clothing instead of placing a loose blanket in the crib.

The academy recommends room sharing without bed sharing, ideally for at least the first six months. A crib or bassinet can stand beside the parents’ bed, making feeding and comforting easier while keeping the baby on a separate surface.

Tummy time remains important for strength and motor development, but it should happen only while the baby is awake and actively supervised. Once babies can roll both ways independently, parents need not reposition them during sleep, though every sleep should still begin on the back.

Young infants may be unable to move their heads or bodies when an object interferes with breathing. Soft bedding can cover the nose and mouth, while another person or animal sharing the surface can obstruct the airway or unintentionally roll onto the baby.

Among 919 deaths attributed to suffocation involving unsafe sleep factors, 74% involved soft bedding blocking the airway. About one in four involved another person or animal obstructing the airway, while 8% involved a baby becoming wedged between objects.

Adult beds are not considered safe infant sleep surfaces, and couches and armchairs can be even more dangerous. Infants can become trapped between cushions, furniture, a mattress, a wall or a sleeping adult.

Parents and caregivers should follow the same sleep practices every time and everywhere a baby sleeps, including while traveling or visiting relatives. They should also prevent exposure to smoking and nicotine during pregnancy and secondhand smoke after birth.

Alcohol, marijuana, opioids and illicit drugs should also be avoided during pregnancy and after delivery. Their use can increase risk during pregnancy and impair a caregiver’s ability to wake and respond to an infant.

Car seats protect babies during vehicle travel, but they are not intended as routine sleep spaces outside the car. After reaching a destination, caregivers should move a sleeping baby from a car seat, stroller or carrier to an appropriate infant sleep surface.

Exhausted parents can keep a crib or bassinet beside their bed to make nighttime feeding easier. If a parent falls asleep while feeding in bed, the baby should be returned to the separate sleep space as soon as the parent wakes.