In this article
- What is SIDS?
- Why does SIDS happen?
- When does SIDS happen?
- Which babies are most at risk?
- How can I reduce my baby's risk of SIDS?
- What about daytime naps?
- What's the advice on using a dummy?
- Can a sleep monitor or other device help?
- Is it safe to sleep with my baby?
- Where can I get more information?
What is SIDS?Sudden infant death syndrome (SIDS), also known as cot death, is a diagnosis that's made when an apparently healthy baby dies, without warning, and for no clear reason (Creery and Mikrogianakis 2006, Hauck and Tanabe 2009).
When a baby dies suddenly, doctors and investigators try to find out why. This includes a post-mortem examination, seeing where the baby died, and a review of the baby's medical notes (Creery and Mikrogianakis 2006).
In less than half of all cases of SIDS, a health condition, illness or accident is found to be the cause.
SIDS is rare, but it is still the most common cause of death in newborn babies (FSID 2011b). Sadly, just over 300 babies die from SIDS in the UK each year (FSID 2011b, Hauck and Tanabe 2009).
Why does SIDS happen?No one knows why some babies die in this way (Hauck and Tanabe 2009). It may just be a combination of factors that affect a baby at a vulnerable stage in their development (FSID 2009).
Some babies may have a problem with the part of the brain that controls breathing and waking. These babies don't respond if their breathing is slightly restricted, such as if there are bedclothes covering their nose or mouth (Kahn and Groswasser 2003).
When does SIDS happen?SIDS most often occurs when a baby is thought to be sleeping. This may be at night, but it could be during a nap at any time of day, in a pram, or even in their parent's arms (BMJ 2011, FSID 2009). SIDS is more common in the winter (BMJ 2011, FSID 2011b), though it's not clear why.
Which babies are most at risk?About 90 per cent of cases of SIDS happen in the first six months. Most are in the first three months of life, peaking in the second month. The risk falls as your baby grows older, and very few deaths from SIDS occur after a year (FSID 2011b).
Remember that SIDS is rare. Most babies pass through the first six months of life without any problems.
It is very rare for SIDS to happen twice in the same family. It is also uncommon in South Asian families, though experts aren't sure why (Ball et al 2011, FSID 2011b). The rate of SIDS is highest for babies of mums who are under 20 years when they have their baby (FSID 2011b).
There are other factors that you can't change, which put a baby at a higher risk of SIDS, including if your baby:
- Is a boy. The ratio of SIDS is about 60:40 boys to girls (FSID 2011b, NHS 2010).
- Was born prematurely (before 37 weeks) (NHS 2010).
- Had a low birth weight of less than 2.5kg (5.5lb) (NHS 2007, FSID 2011b).
How can I reduce my baby's risk of SIDS?Sadly, there's no failsafe way to prevent SIDS. However, you can do a number of things to keep your baby safe and reduce the risk.
Put your baby to sleep on her back, in a cot or Moses basket. For the first six months this should be in a room with you (FSID 2011a).
Healthy babies placed on their back to sleep are not more likely to choke (BMJ 2011). This is the safest place and position for your baby to sleep in (Hauck and Tanabe 2009).
At about five months or six months, babies start to roll. At this age the risk of cot death reduces and it's safe to let your baby find her own comfortable sleeping position. But you should still put your baby down to sleep on her back.
If you wake up and see that your baby is on her front, and she's younger than six months old, gently roll her on to her back. Babies older than this can usually roll on to their backs themselves (FSID 2011a). You don't need to get up and check throughout the night, as she's likely to change position regularly when she sleeps (FSID 2011a).
Don't smoke during pregnancy or allow anyone to smoke around your baby. If you smoke during or after pregnancy, your baby's risk of SIDS increases (BMJ 2011, Hauck and Tanabe 2009). SIDS is more common in babies who are regularly exposed to smoke (Hauck and Tanabe 2009).
The risk to your baby is increased if anyone in the house smokes, even if it's in another room with a window open. Visitors should smoke outside so the air around your baby is always smoke-free. Never smoke in the same room as your baby (BMJ 2011), or in a car with your baby. It's actually against the law for anyone to smoke in a car when someone under 18 is present (Gov UK 2015).
The following may also reduce your baby's risk of SIDS, though the evidence is less clear (Hauck and Tanabe 2009).
Don't let your baby get too hot. Overheating is linked to an increased risk of SIDS. Keep the room your baby sleeps in at a comfortable temperature of between 16 degrees C and 20 degrees C (DH 2009). Don't put your baby's cot near a radiator, heater or fire, or in direct sunlight. And never place a hot water bottle or an electric blanket in your baby's bed.
Lay your baby with her feet at the foot of her cot, so she can't wriggle down under the bedding. Keep her head uncovered by tucking her bedding in no higher than her shoulders. If you use a sleeping bag, make sure it is well-fitting, so your baby can't slide down inside.
Signs that your baby may be too hot include:
Remove your baby's hat and any extra layers of clothing as soon as you come indoors after being outside, even if it means waking her up (DH 2009).
Never sleep on a sofa or armchair with your baby (FSID 2011a). After a cuddle or a feed, put her back in her cot on a firm, flat mattress that is clean and fits well, without gaps at the edges. Waterbeds, beanbags, baby nests, fleeces and other soft surfaces are not suitable for your baby to sleep on. The outside of the mattress should be waterproof and covered with a single sheet.
Rather than a duvet, use a sheet and cellular blankets or a lightweight baby sleeping bag that's the correct size. That way your baby can't slip down inside (FSID 2011a).
If your baby is too hot, remove a blanket. If she's cold, add one. One blanket folded in half is two layers. Don't use duvets, quilts, bedding rolls or pillows if your baby is under a year old (FSID 2011a).
Breastfeed your baby if you can, as breastfeeding may reduce the risk of SIDS in babies (Ip et al 2007, Hauck and Tanabe 2009). Breastmilk also increases your baby's resistance to infections (DH 2009).
Take your baby for regular check-ups and keep up to date with her immunisations (DH 2009). Seek medical advice if your baby is unwell.
What about daytime naps?Follow the advice for safe sleeping when your baby has her daytime naps, as well as when she goes to sleep at night (Blair et al 2006). Lay her down to sleep on her back and make sure she can't cover her head with her bedclothes.
For the first six months try to have your baby in the same room as you when she takes her naps. A Moses basket, carrycot or travel cot is a good way to keep her nearby while you get on with what you want to do.
What's the advice on using a dummy?Using a dummy when you settle your baby to sleep, even for a nap, may reduce the risk of SIDS, but more research is needed (AAP 2005, DH 2009, Hauck and Tanabe 2009). One theory is that the handle of the dummy may help air to get to your baby's airways, even if her face is covered by bedclothes.
Using a dummy may also help to strengthen the nerves that control your baby's upper airway (NHS 2010).
If you decide to use a dummy, you should wait before breastfeeding is established (FSID 2011). This is usually by the time your baby is about six weeks old. And try to wean your baby off her dummy by the time she is a year old (DH 2009).
Don't worry if the dummy falls out while your baby is asleep. And if your baby doesn't like using a dummy, don't force her to take one.
Can a sleep monitor or other device help?A breathing monitor may be recommended by your doctor if your baby has already had a life-threatening breathing incident, or has other problems that might increase his risk of SIDS (BMJ 2011). However, healthy babies don't need a breathing monitor, and there's no evidence that they prevent SIDs (BMJ 2011, DH 2009).
Is it safe to sleep with my baby?Some mums find breastfeeding easier if their baby shares the bed with them. But the safest place for your baby to sleep for the first six months is in a cot or Moses basket in the same room as you.
Never share a bed with your baby if you or your partner:
- are a smoker (even if you never smoke near your baby)
- have been drinking alcohol
- are taking any medication or drugs
- are very tired (Carpenter et al 2013)
- was premature (born before 37 weeks)
- weighed less than 2.5kg at birth (5.5lb) (DH 2009, FSID 2011a)
Where can I get more information?The Lullaby Trust offers lots of information, and you can talk to your health visitor if you are worried about SIDS.
Last reviewed: July 2012
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