Baby Sleep Safety: A Guide to Safer Sleep (NHS & Lullaby Trust Guidance)

This article summarises official UK safer sleep guidance from the NHS and The Lullaby Trust. It is general information, not medical advice — if you have specific concerns about your baby’s sleep, health visitors and GPs can give guidance tailored to your child.

Sudden Infant Death Syndrome (SIDS) is rare, but safer sleep practices measurably reduce the risk, and the guidance is consistent, specific and freely available from the NHS and The Lullaby Trust. Since 1991, an estimated 31,951 babies’ lives have been saved in the UK through the adoption of safer sleep advice, according to The Lullaby Trust. This guide sets out the current guidance in plain terms.

The core rules

1. Always place your baby on their back to sleep

This applies to every sleep, day and night, until your baby is 12 months old — not just at bedtime. The NHS is explicit that babies should not be put down to sleep on their side or front. If your baby can roll over on their own once they’re a bit older, you don’t need to keep turning them back over, but you should always start every sleep on their back.

2. Keep your baby in your room for the first six months

Both the NHS and The Lullaby Trust recommend room-sharing — baby sleeping in the same room as you — for at least the first six months, for every sleep, day and night. This should be on a separate, baby-specific sleep surface (a cot, Moses basket, crib or travel cot next to your bed), not in the bed with you.

3. Use a firm, flat, waterproof mattress

The mattress should be firm and flat — soft or padded surfaces increase risk. The NHS guidance is specific: your baby’s head should not sink into the mattress by more than a few millimetres. A new mattress is preferable; a previously-used one is generally considered acceptable only if it has been stored clean, dry and in a smoke-free environment, and you’re confident of its history and condition.

4. Keep the cot clear

No pillows, duvets, cot bumpers, soft toys, comforters, positioning wedges or straps, and no pods or nests on the mattress. The NHS advises making sure there is nothing in the cot that could cover your baby’s mouth or nose. If you use blankets, they should be tucked in firmly, no higher than your baby’s shoulders, and not doubled over. Baby sleeping bags of an appropriate tog rating for the room temperature are a widely recommended alternative, and when using one, there should be no other bedding in the cot.

5. Keep the room at the right temperature

The Lullaby Trust recommends a room temperature of 16–20°C. Getting too hot is a known risk factor for SIDS, so this is worth checking with a room thermometer rather than guessing, particularly in winter with heating on or in summer heatwaves.

6. Keep your baby’s environment completely smoke-free

Both organisations are unambiguous: the risk of SIDS is significantly higher if a parent smoked during pregnancy or smokes after the baby is born, and this includes exposure to secondhand smoke in the home and car.

Co-sleeping and where risk increases sharply

Co-sleeping (sharing a bed with your baby) carries increased risk in certain circumstances, and the NHS specifically advises against bed-sharing if you or your partner:

• Smoke (regardless of where or when)
• Have been drinking alcohol
• Have taken recreational drugs
• Have taken medication that causes drowsiness
• Are extremely tired

Separately, and importantly, the NHS warns that falling asleep on a sofa or armchair with your baby — even briefly, even if you didn’t intend to — can increase the risk of SIDS substantially, more so than planned bed-sharing. If you’re feeding at night and worried about dropping off, it’s worth thinking in advance about how to reduce that risk — for example, planning feeds somewhere you’re less likely to fall asleep, or having a partner on hand to take the baby if you do doze off.

Choosing sleep equipment

When buying a cot, crib, Moses basket or travel cot, look for products that meet the relevant British Standard and carry that certification clearly on the packaging or listing — this applies whatever brand or retailer you buy from. Beyond compliance, the safety fundamentals above (firm flat mattress, no loose bedding, correct room temperature) matter far more than any marketed “extra” feature. If you’re comparing baby sleep and nursery equipment on For Baby Boss, use the safer sleep rules above as your checklist regardless of which product you’re looking at.

Where to get further guidance

This article summarises the headline rules, but The Lullaby Trust and NHS websites go into more detail on specific situations — premature babies, twins, illness, travel, and more — and their pages are kept up to date as guidance evolves. If you have any concern about your baby’s sleep, breathing or wellbeing, contact your health visitor, GP or NHS 111 rather than relying on general guidance alone.

Sources

• NHS — Safe sleep advice for babies (accessed September 2026)
• The Lullaby Trust — Safer sleep overview (accessed September 2026)
• The Lullaby Trust — Co-sleeping (accessed September 2026)