Sudden Infant Death Syndrome (SIDS), sometimes called cot death, is the sudden and unexplained death of a baby who seemed healthy, usually during sleep. It is most common in the first six months of life. Its exact cause is not fully understood, but research has identified clear steps that greatly reduce the risk. Campaigns such as “Back to Sleep” in the 1990s led to large falls in SIDS deaths in many countries.
Nurses, midwives and health visitors are the professionals most parents see in the early weeks. Clear, practical and non-judgemental safe sleep advice is one of the most valuable things we can give.
The key safe sleep messages
1. Always place babies on their back to sleep
- For every sleep, day and night, from birth.
- Side sleeping is not safe; babies can roll onto their tummies.
- Once babies can roll from back to front and back again by themselves (usually around 5 to 6 months), they can be left in the position they choose, but should still be placed on their back to start.
- Parents often worry babies will choke if they vomit on their back. Healthy babies have reflexes that protect the airway, and research shows back sleeping does not increase choking.
2. A clear, flat, firm sleep space
- A firm, flat, waterproof mattress in good condition, in a cot, crib or Moses basket.
- No pillows, duvets, quilts, bumpers, soft toys or positioning wedges.
- Babies shouldn’t sleep on sofas, armchairs, beanbags, waterbeds or inclined products.
- Car seats are for travel. Babies shouldn’t sleep in them for long periods outside the car.
3. “Feet to foot” and light bedding
- Place the baby with feet at the foot of the cot so they can’t wriggle down under covers.
- Use a well-fitting baby sleeping bag, or firmly tucked light blankets no higher than the shoulders.
4. Avoid overheating
- Keep the room at a comfortable temperature; around 16 to 20°C is often recommended in cooler climates.
- In hot climates, use light cotton clothing, ensure ventilation and avoid heavy wrapping or hats indoors.
- Check the baby’s temperature by feeling the chest or back of the neck, not hands and feet. If sweaty, remove a layer.
5. A smoke-free environment
- Smoking in pregnancy and exposure to smoke after birth strongly increase SIDS risk.
- Encourage parents and household members to quit, and offer referral to stop-smoking services.
- No one should smoke in the house or car, even with windows open.
6. Room sharing for the first 6 months
Having the baby sleep in a separate cot or crib in the parents’ room for at least the first six months is recommended by many health bodies.
7. Breastfeeding
Breastfeeding is associated with a lower risk of SIDS. Support mothers to breastfeed for as long as they wish.
8. Dummies (pacifiers)
Some evidence suggests offering a dummy at sleep times may reduce risk. If used, wait until breastfeeding is established (often around 4 weeks), don’t force it, and don’t coat it in anything sweet.
Co-sleeping and bed-sharing
In many cultures, sharing a bed with a baby is normal and expected, and many parents fall asleep with their baby during night feeds. Simply telling parents “never bed-share” often doesn’t work and may lead to more dangerous situations, such as falling asleep with a baby on a sofa.
A harm-reduction approach, used by organisations such as the UK’s Lullaby Trust and UNICEF UK Baby Friendly Initiative, gives parents honest information:
Never bed-share, and never sleep with a baby on a sofa or armchair, if:
- Either parent smokes
- Either parent has drunk alcohol or taken drugs, including medicines that cause drowsiness
- The parent is extremely tired
- The baby was born premature (before 37 weeks) or with a low birth weight (under 2.5 kg)
If parents do bed-share, they can make it safer by:
- Using a firm, flat mattress and keeping pillows and adult bedding away from the baby
- Placing the baby on their back, not between two adults
- Making sure the baby can’t fall out of bed or get trapped between the mattress and wall
- Keeping pets and other children out of the bed
Additional risks to discuss
- Swaddling: if parents swaddle, use thin material, keep it loose around the hips, never cover the head, and stop as soon as the baby shows signs of rolling.
- Slings and carriers: the baby should be upright, close enough to kiss, with the face visible and chin off the chest.
- Products marketed as “safe sleep” aids: wedges, nests and positioners are not recommended.
- Home monitors: breathing and movement monitors haven’t been shown to prevent SIDS and shouldn’t replace safe sleep practices.
Babies at higher risk
- Premature or low birth weight babies
- Babies exposed to smoke in pregnancy
- Boys (slightly higher risk)
- Babies of young mothers or families facing social disadvantage
- Babies with a sibling who died suddenly
Extra support and repeated advice are especially important for these families.
How to give advice that works
- Start before birth in antenatal clinics and classes.
- Repeat it at discharge, postnatal visits and immunisation clinics.
- Show, don’t just tell. Model safe sleep on the postnatal ward: babies on their backs in clear cots.
- Ask about real life. “Where does your baby sleep at night? What happens during night feeds?”
- Involve the whole family, including grandparents, who may have learned different advice years ago.
- Be respectful of culture. Work with families to find safe options that fit their beliefs and living conditions.
- Use written materials in the family’s language.
If the worst happens
Losing a baby suddenly is devastating. Families need compassionate support, clear information and access to bereavement services. Nurses should avoid any language that suggests blame. Follow local procedures for sudden unexpected infant death, which usually involve the police and coroner or equivalent, and ensure parents are supported throughout.
Summary for parents (the simple version)
- Back to sleep, every sleep.
- Clear cot: firm, flat mattress, nothing else.
- Feet to foot, light covers, not too hot.
- Smoke-free before and after birth.
- Baby in your room for 6 months.
- Never sleep with your baby on a sofa or armchair.
- Breastfeed if you can.