Meaning of crib death: The older everyday name for a baby dying without warning during sleep, with no cause found afterward.

Definition of crib death

Crib death is the older common name for the sudden death of an apparently healthy baby under one year of age, usually during sleep. Nothing in the history, in the examination of the place of death or in the autopsy explains it. Medical records now use the term sudden infant death syndrome, and cot death is the British equivalent.

Why did the name change?

Crib death describes where a baby was found rather than anything about the death itself, and the crib plays no causal part. The medical term, sudden infant death syndrome, states the two things actually known: the death was sudden and the infant was under a year old. The change also reflects a wider grouping. Investigators now speak of sudden unexpected infant death, covering every sudden death in this age group, and reserve SIDS for the portion that stays unexplained after a full investigation. Accidental suffocation and undiagnosed illness account for much of the remainder. Everyday speech and older records still use the crib death wording, so the two terms sit side by side in many family histories.

What is understood about why it happens?

No single cause has been found. The explanation most often used is the triple risk model, which holds that three things must coincide.

ElementWhat it means
Underlying vulnerabilityImmature control of breathing, heart rate or waking
Critical periodThe early months, while those systems mature
Outside stressorFace-down position, soft bedding, overheating, covered airway

None of the three alone is enough. Studies of brainstem tissue have found differences in the serotonin systems that help drive the reflex rousing a baby and restoring breathing when oxygen falls.

What changed the rates?

Public campaigns encouraging infants to be placed on the back to sleep were followed by a steep fall in deaths across many countries, the clearest change in the history of the condition. Other factors identified by research include smoking during pregnancy and in the home, soft bedding and loose covers, overheating, and sleeping surfaces not designed for infants. Rates are higher in premature and low birth weight babies and higher in boys. Deaths cluster in the months when rousing from a sleep stage is still poorly regulated, which is where the underlying vulnerability sits.

Also known as

cot deathSIDSsudden infant death syndrome

Used in a sentence

The family history recorded a sibling lost to crib death in infancy.

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Good to know

Crib death and sudden infant death syndrome name the same thing, and the label is applied only after autopsy, scene examination and clinical history have found no explanation.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.