Loose blankets in the infant sleep space are one of the most commonly identified suffocation hazards — and one of the most commonly present. The safe, equivalent alternative (the infant sleep sack) has been available for decades and is straightforward to use. Understanding why loose blankets are dangerous and why sleep sacks are the preferred alternative helps families make confident choices.
Healthbooq provides accurate, evidence-grounded infant safe sleep guidance.
Why Loose Blankets Are Risky
Face coverage. Loose blankets can be kicked or moved so that they cover the infant's face, obstructing breathing. An infant under approximately 4–5 months does not yet have the motor ability to remove a covering from their face. This is the primary suffocation mechanism.
Entrapment. Blankets can bunch under the baby's face, around the neck, or across the body in ways that reduce airflow.
Overheating. A blanket that stays in place may produce more warmth than intended, contributing to overheating — a SIDS risk factor.
The Safe Alternative: Infant Sleep Sacks
An infant sleep sack (also called a baby sleeping bag) is a wearable blanket with a zip opening and armholes but no hood or foot opening. Because it is worn (not lying loose in the cot), it cannot travel to cover the infant's face. The infant's head remains uncovered.
Sleep sacks are rated in togs (insulation units) and should be matched to the room temperature:
- High tog (2.5): for cooler rooms (under 18°C)
- Medium tog (1.0): for the 16–20°C recommended range
- Low tog (0.5): for warmer rooms (20–24°C)
- Very light (0.5 or lighter): for summer (above 24°C)
If a Blanket Is Used
For infants over approximately 6–7 months who can reposition themselves, a thin blanket can be used with appropriate precautions:
- Use a thin blanket (not a duvet or heavy quilt)
- Tuck the blanket in securely at the sides and foot of the cot
- Position the blanket no higher than the infant's shoulders
- Place the infant at the foot of the cot (feet-to-foot position) to prevent them from slipping under the blanket
A sleep sack remains the safer option even for older infants.
Key Takeaways
Infants under 12 months do not need loose blankets for warmth — and loose blankets are a suffocation hazard. The safe alternative is an appropriately-rated infant sleep sack (sleeping bag), which provides equivalent warmth without the risk of covering the infant's face. If a blanket is used, it should be thin, tucked in at the sides and foot of the cot, and positioned no higher than the infant's shoulders.
