Health A to Z
Sudden infant death syndrome (SIDS) – sometimes known as 'cot death' – is the sudden, unexpected and unexplained death of an apparently healthy baby.
In the UK, just under 300 babies die suddenly and unexpectedly every year. This statistic may sound alarming, but SIDS is rare and the risk of your baby dying from it is low.
Most deaths happen during the first six months of a baby’s life. Infants born prematurely or with a low birthweight are at greater risk. SIDS also tends to be slightly more common in baby boys.
SIDS usually occurs when a baby is asleep, although it can occasionally happen while they're awake.
Parents can reduce the risk of SIDS by not smoking while pregnant or after the baby is born, and always placing the baby on their back when they sleep (see below).
The exact cause of SIDS is unknown, but it's thought to be down to a combination of factors.
Experts believe SIDS occurs at a particular stage in a baby’s development, and that it affects babies who are vulnerable to certain environmental stresses.
This vulnerability may be caused by being born prematurely or having a low birthweight, or because of other reasons not yet identified.
Environmental stresses could include tobacco smoke, getting tangled in bedding, a minor illness or a breathing obstruction. There's also an association between co-sleeping (sleeping with your baby on a bed, sofa or chair) and SIDS.
Babies who die of SIDS are thought to have problems in the way they respond to these stresses and how they regulate their heart rate, breathing and temperature.
Although the cause of SIDS isn't fully understood, there are a number of things you can do to reduce the risk.
Below is a list of things you can do to help prevent SIDS.
Read more about reducing the risk of SIDS.
Babies often have minor illnesses, which you don't need to worry about. Give your baby plenty of fluids to drink and don't let them get too hot.
If you're worried about your baby at any point, see your GP or call NHS 111 for advice.
Dial 999 for an ambulance if your baby:
Read more about spotting signs of serious illness in children.
If a baby dies suddenly and unexpectedly, there will need to be an investigation into how and why they died. A post-mortem examination will usually be necessary, which can be very distressing for the family.
The police and healthcare professionals work closely to investigate unexpected infant deaths and ensure the family is supported. They should be able to put you in touch with local sources of help and support.
Many people find talking to others who have had similar experiences helps them to cope with their bereavement.
The Lullaby Trust provides advice and support for bereaved families. Specially trained advisers are available on their helpline. The number is 0808 802 6868 and it's open Monday to Friday (10am-5pm), and at weekends and public holidays (6pm-10pm). You can also visit their website for further information and support if you are bereaved.
Read more about bereavement.
If your baby was affected by SIDS, your clinical team will pass information about him or her on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).
This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.