Unexplained infants deaths accounted for 9% of deaths among babies in 2013 (Figures from National Office of Statistics, 2013). Thankfully, sudden unexplained infant deaths are rare.

However, in 2013, there were 249 unexplained infant deaths in England and Wales which is a rate of 0.36 deaths per 1,000. This is the first rise in unexplained infant deaths since 2008. It is, therefore, important to take prevention of cot death seriously to help protect your baby.

How do I reduce the risk of cot death?

The most important thing you can do to help protect your baby from cot death is to not smoke during pregnancy or around your baby. Also, don’t let your partner (or people who live in your house) smoke in the house or around you when you are pregnant or smoke in the house or car after your baby is born. In the UK, it is illegal to smoke in a car when a child under 18 is present.

The smoke from cigarettes is the biggest contributing cause of SIDS deaths.

In addition, the Lullaby Trust (previously known as the Foundation for the Study of Infant Deaths) and the Department of Health have outlined the steps parents can take to reduce the risk of cot death:

• Breastfeed your baby.
• Place your baby on their back to sleep.
• Share a bedroom with your baby.
• Put your baby in a cot or Moses basket right next to your bed.
• Quit smoking before you become pregnant.
• Keep your baby’s head uncovered when they sleep – no hats or covers.

• Smoking during pregnancy.
• Smoking near your baby or in your house.
• Sharing a bed with your baby if you have been drinking alcohol, if you take drugs or if you are a smoker.
• Never sleep with your baby on a sofa or armchair.
• Letting your baby get too hot.

One theory is that a parent’s breathing rhythm helps to regulate their baby’s breathing. Also, the noise of another person in the room with the baby helps to keep babies aroused and coming into periods of light sleep during the night. This arousal, as well as waking for night feeds is important and functional in babies. Breastfeeding at night also protects babies from SIDS and this is easier if your baby shares your room at night.

The feet to foot and back to back campaign, that was rolled out in 1991 in the UK (which also included the no smoking message) and had a huge impact on reducing cot death with a 65% reduction in cot deaths by the year 2013 (National Office of Statistics, 2013).

Very little babies can be difficult to put to sleep on their back because they are still in the foetal position, with their backs in a concave position. However, it really helps to protect them from SIDS to put them to sleep on their back. If you are struggling, it can help to tuck them into their cot, Moses basket or sleeping space snugly, especially around their hips and legs, to help them to feel secure and sleep on their backs.

Babies that are put to sleep on their fronts or sides are at increased risk of SIDS. If you notice your baby is on their side or front and asleep, gently put them back on their backs. However, in older babies that can roll from their front to their back and back again, you can leave them to change positions at night.

Since our hunter-gatherer origins, babies have shared a sleeping space with their mums. Today babies sometimes share their parents’ bed at night time. Co-sleeping has pros and cons that you need to be aware of.

The Baby Sleep Information Source (BASIS) is funded by Economic and Social Research Council and managed by Professor Helen Ball and the Durham University Parent-Infant Sleep Lab. ISIS has a strong evidence base with an interest in supporting breastfeeding with senior representatives from La Leche League, NCT, and UNICEF UK Baby Friendly Initiative.

BASIS report that bringing a baby into an adult bed (bed-sharing) is common with around half of all babies in the UK have slept in their parents’ bed by the time they are 12 weeks old. Official advice says it is important parents are fully informed about the risks of co-sleeping and situations where it may not be the safest choice.

However, BASIS has attempted to investigate SIDS studies to try and tease apart when bed sharing is a risk factor for SIDS. Here is what they report.

The CESDI UK SIDS study looked at SIDS deaths between 1993-1996 and found that bed sharing didn’t increase the risk of SIDS if the parents were non-smokers and the baby was over 14 weeks of age. Furthermore, a more recent UK study looked at SIDS deaths between 2003-2006 highlighted that smoking, alcohol use and sofa-sharing explained the increased risk of SIDS deaths that occurred when babies were co-sleeping with an adult. A Scottish SIDS study looked at SIDS deaths between 1996-2000 again found that bed-sharing was associated with an increased risk of SIDS for babies younger than 11 weeks. Unfortunately, this study didn’t record whether the parents of these babies had smoked in pregnancy or consumed alcohol consumption when the unexplained death occurred. A SIDS study in the Republic of Ireland looked at SIDS deaths between 1994-2001 reported bed-sharing was associated with an increased risk of SIDS for babies less than 10 weeks of age, but not for older babies whose mothers did not smoke during pregnancy.

BASIS state that the most recent studies have tried to tease apart the particular risk factors when babies have died during bed-sharing. They highlight that the deaths occur when a parent sleeping with their baby is a smoker, has consumed alcohol or has taken either illegal or over the counter drugs that cause deep sleep. So your baby will be safer sleeping in a cot rather than your bed if you or your partner are a smoker, if you drink alcohol, or if you take medication or drugs that make you drowsy.

Breastfeeding helps to protect babies from SIDS or cot death and bed-sharing is strongly associated with breastfeeding with 70-80% of breastfed babies sleeping with their mother or parents some of the time in the first weeks after birth. ISIS goes on to report that many studies have reported that bed-sharing babies breastfeed for longer than babies who sleep in a cot in the parents’ bedroom or a cot in their own room. Other parents report bed sharing to bond with their baby or to keep an eye on their baby when they are ill. The danger of falling asleep with your baby on a sofa or armchair is that a baby can get trapped between the adult and the cushions and be suffocated.

ISIS concludes by stating that before you co-sleep with your baby, consider whether you are happy it is safe.

The Lullaby Trust raises awareness about sleep safety and offers support for parents bereaved by SIDS. They are more cautious in their advice and do not recommend bed-sharing with your baby if:

• Your baby had a low birth weight (2.5kg or 2lbs or less).
• Your baby was born prematurely before 37 weeks or less.
• You or your partner smoke at all.
• You or your partner have consumed alcohol.
• You or your partner have taken any drug or medication which makes you drowsy.

Furthermore, they caution special care not to fall asleep giving night feeds in a bed or on an armchair or sofa with your baby. The Lullaby Trust go on concluding that a high proportion of babies who die of SIDS are found with their heads covered by bedding – so there should be no pillows or bedclothes that could cause your baby to overheat or suffocate. They recommend a baby cot that comes close to your bed so your baby is in their own bed space but still close to you.

The room where your baby sleeps should be at around 16-20 degrees Celsius to prevent your baby overheating in the night. This is quite a cool temperature but the good news is that babies actually sleep best at around 18 degrees so it’s not too cold for a good night’s sleep.

You also need to avoid hats, duvets, and pillows so that your baby doesn’t overheat or suffocate. The safest place for babies to sleep in the first six months is in their parents’ room which means you will be there to monitor the room temperature. Feel the back of your baby’s neck and tummy to check they are not too hot. If they are hot or sweaty, remove a layer of bedding. If your baby has a fever, they will need fewer covers, not more. Babies with a fever need to be monitored throughout the night.

Your baby’s cot mattress needs to be firm and flat and be the correct size for the cot or Moses’ basket. It should have a waterproof cover that can be wiped down. There is a link (though it may not be a causal link) to second-hand mattresses and increased risk of SIDS. If possible buy a new mattress for each baby. If you do have to use a second-hand mattress make sure it is firm, flat and is the right model for your baby’s cot. Make sure it had a waterproof cover on it previously and make sure it has a waterproof cover now.

• Avoid pillows as they more than double the risk of SIDS and babies do not need them.
• Avoid duvets or bulky bedding.
• Opt for natural fibres such as cotton sheets or cotton cellular blankets.
• Avoid cot bumpers as they can pose a risk to babies of suffocation and avoid other items in the baby cot such as big soft toys.

The advice around dummies is slightly complicated. Two meta-studies by the Cochrane Collaboration concluded that dummies do not interfere with breastfeeding with mums who are determined to breastfeed and in fact may protect babies from SIDS (Sudden Infant Death Syndrome). No-one knows why dummies may offer protection from SIDS; maybe babies with dummies are checked more frequently, maybe the sucking motion stimulates the babies breathing and prevents apnea (or stopping breathing), it’s hard to know as there are many variables involved.

The protective effect of dummies and pacifiers only seemed to hold for babies that always used a dummy or pacifier. Babies that didn’t use a dummy or pacifier didn’t get added protection and babies that did use one then needed to use it for every sleep. If you choose to introduce a dummy or pacifier you need to be consistent and use it for each sleep and nap.

The Lullaby Trust does not recommend or caution against swaddling but they do offer the following recommendations if you do choose to swaddle your baby:

• Use thin, natural materials as a swaddling cloth such as cotton.
• Do not swaddle your baby above their shoulders (some swaddling practices around the world swaddle the whole head too).
• Do not put a swaddled baby to sleep on their front.
• Do not swaddle your baby too tight.
• Check the baby’s temperature to ensure they do not overheat.

Although ISIS acknowledge that swaddling can help babies to sleep they are more cautious about swaddling for the reason that babies may sleep more deeply than is optimal (babies need to and should rouse throughout the night). They advise parents who choose to swaddle their babies to do so from birth (rather than start at the peak risk period for SIDS at around 2-3 months of age). ISIS also point out that swaddling isn’t a good idea if you are co-sleeping with your baby.

Although premature babies may have slept on their fronts in NICU (Newborn Intensive Care Unit) for a medical reason, The Lullaby Trust recommend that when your premature baby leaves the hospital (and the safety of continual monitoring) they should sleep on their backs like other babies.

In summary, SIDS is thankfully a rare (though devastating) event. The good news is that scientists and doctors have quite a strong understanding of the factors that help protect babies from SIDS. There are lots of actions you can take to minimise the chance of SIDS, the first one being to stop smoking as soon as you plan to have a baby and don’t let anyone smoke near your baby or in your car or house.

Babies should also share a room with their parents for the first six months to help protect them during the peak time of SIDs (around 2-3 months after birth) and then follow the advice on safe sleeping.

Donnelly, W. T., Bartlett, D., and Leiter, J.C. (2016), Serotonin in the solitary tract nucleus shortens the laryngeal chemoreflex in anaesthetized neonatal rats. Exp Physiol. Accepted Author Manuscript. doi:10.1113/EP085716

Jaafar et al (2011) Pacifier use versus no pacifier use in breastfeeding term infants for increasing duration of breastfeeding (Review) The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.