What to put in the cot (and what to leave out)

The safest cot is the emptiest one. For the first 12 months, your baby's sleep space should contain two things: a firm, flat mattress and a single fitted sheet. Everything else — however well-marketed, however instinctively reassuring — either adds no benefit or adds risk.¹

What goes IN the cot

A firm, flat mattress

The mattress is the only piece of cot equipment that directly affects safety.

The firmness test: press the centre of the mattress firmly with your closed fist. It should spring back immediately and completely. If it moulds around your hand, holds a dent, or feels springy-soft, it is not suitable for infant sleep. A mattress that feels uncomfortably hard to an adult is the right texture for a baby.

The mattress must also be flat — inclined mattresses and wedges are not safe and are not recommended by the AAP or FDA.¹²

Use a mattress designed for the specific cot or crib you have. There should be no gap wider than two fingers between the mattress edges and the cot sides. Gaps are entrapment hazards.

A fitted sheet

One fitted sheet, correctly sized for the mattress. It should be taut with no slack, no loose corners, and no ability to pull free. That's the complete bedding setup.

A sleep sack (for warmth)

If your baby needs warmth beyond a fitted sheet, a wearable blanket — sleep sack, grow bag, or sleeping bag — is the safe alternative to loose blankets. Choose the tog rating appropriate for your room temperature.

What stays OUT of the cot

Bumpers — including "breathable" mesh

Cot bumpers were originally designed to prevent babies getting limbs trapped between cot bars. Modern cot bar spacing regulations have made this unnecessary. The bumpers themselves have caused infant deaths: from suffocation when a face is pressed against them, from entrapment in the gap between bumper and mattress, and from strangulation on ties.

"Breathable" mesh bumpers are marketed as a safer alternative. They are not. Several infant deaths have been linked to mesh bumpers, and they remain associated with suffocation and entrapment risk.¹³ The AAP recommends against all cot bumpers.¹

Loose blankets, quilts, and duvets

A blanket that moves across a baby's face can cause rebreathing of carbon dioxide or airway obstruction. Infants under 12 months do not have reliable enough head control or muscle strength to move their face clear. Quilts and duvets create the additional risk of overheating, which is also a SIDS risk factor.

Use a sleep sack instead. They cannot migrate over the face.

Pillows

No pillow in the cot until at least 18–24 months. Infant airways can be blocked by soft surfaces, and babies don't yet have the muscle control to move their heads away from an obstruction. A firm, flat mattress surface is everything a newborn needs.

Soft toys and stuffed animals

Any soft object near an infant's face is a potential suffocation hazard. Keep stuffed animals and soft toys out of the cot for the first 12 months. They can go in once your baby is old enough to actively move them and has a reliably protected airway.

Sleep positioners, nests, and wedges

Products marketed as "nests," "pods," snuggle positioners, or inclined sleepers claim benefits including reduced reflux, reduced flat-head risk, or improved sleep. None of these claims have robust evidence behind them. Multiple infant deaths have been linked to these products, as babies can roll into a position within the device that obstructs their airway.¹²

The AAP recommends against all sleep positioners and inclined sleep surfaces for infants.¹ The FDA has taken enforcement action against several categories of these products.²

Weighted blankets, swaddles, and sleep sacks

Weighted products designed for adult anxiety relief have been repackaged and marketed for infants. The FDA explicitly warns against using any weighted product with infants, and has issued enforcement actions against manufacturers.² These products restrict normal movement, can impair a baby's ability to rouse or reposition, and have been linked to deaths.

The NHS and The Lullaby Trust similarly advise against weighted infant sleep products.³⁴

Overheating: the invisible risk

Room temperature matters alongside the sleep environment. Overheating is an independent SIDS risk factor. The recommended room temperature for infant sleep is 16–20°C (61–68°F).³⁴

Signs your baby is too warm: sweating, flushed skin, damp hair. Signs too cold: cold ears, pale skin, feels cool to the touch on the chest.

Check your baby's temperature at the chest or back of the neck — not the hands or feet, which are normally cool in young infants.

The principle underneath all of this

Every item that has been removed from the list of acceptable cot contents was removed after deaths were linked to it. These aren't overcautious guidelines — they're responses to real harm. The bare cot is not spartan. It's exactly right.

← Back to the complete guide: Safe sleep and newborn sleep

Also in this cluster: Back to sleep · Room sharing

Sources

1. American Academy of Pediatrics. "Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment." Pediatrics 150(1), 2022. https://publications.aap.org/pediatrics/article/150/1/e2022057990/188304/Sleep-Related-Infant-Deaths-Updated-2022-Recommendations
2. NHS. "Reduce the Risk of Sudden Infant Death Syndrome (SIDS)." NHS, 2024. https://www.nhs.uk/conditions/baby/caring-for-a-newborn/reduce-the-risk-of-sudden-infant-death-syndrome/
3. U.S. Food and Drug Administration. "Do Not Use Weighted Infant Products." FDA Consumer Update, 2022. https://www.fda.gov/consumers/consumer-updates/dont-use-weighted-infant-products
4. The Lullaby Trust. "Safer Sleep Advice." 2024. https://www.lullabytrust.org.uk/safer-sleep-advice/