What is the safest way for my baby to sleep?

The core rules

• Back to sleep, every time, for every sleep — day naps included. Once babies can reliably roll both ways (usually 5–6 months), you don't need to physically turn them back if they roll themselves.
• A clear, flat sleep surface — firm mattress, fitted sheet, nothing else. No pillows, cot bumpers, loose blankets, sleep positioners or soft toys until at least 12 months.
• Room-share, don't bed-share, for the first 6 months — baby's own crib or Moses basket in your room significantly lowers SIDS risk versus a separate room.
• Feet to foot — if using a blanket, tuck it in no higher than the shoulders with feet at the foot of the cot, so baby can't wriggle under it. Many parents use a sleeping bag instead, which removes this risk entirely.

What increases risk, specifically

Smoking (in pregnancy or around baby), sofa-sleeping with a baby, and bed-sharing after alcohol, drugs, if you smoke, or if you're unusually exhausted, are the factors most strongly linked to SIDS in the evidence. Overheating is a real risk too — dress for room temperature, not for a photo.

The protective factor worth knowing

Breastfeeding is independently linked with lower SIDS risk, and a dummy at sleep times (once breastfeeding is established, from around 3–4 weeks if bottle feeding from birth) is protective too, even if it falls out during sleep. See The Lullaby Trust for the full guidance.