Sharing a bed with your baby ups risk of cot death

Behind the Headlines

Tuesday May 21 2013

Despite fears, sudden infant death syndrome is rare

"Bed-sharing 'raises cot death risk fivefold'," BBC News reports. The news has featured in much of the media, with headlines based on a large analysis of previous studies into the risk of cot death, or sudden infant death syndrome (SIDS), associated with bed-sharing.

Bed-sharing is where babies sleep in the same bed as their parents. It has long been known that bed-sharing with a parent who smokes or has consumed drugs or alcohol increases the risk of SIDS.

This new study aimed to see if bed-sharing still increased the risk of SIDS in the absence of these risk factors.

The researchers found a fivefold increase in the risk of SIDS associated with bed-sharing in breastfed babies who were under three months old, had parents who did not smoke, and when the mother had not had any alcohol or drugs.

The risk of SIDS was even higher when the parents smoked, drank or used drugs.

It is important to note that the researchers did not conclude that babies should not be brought into their parents' bed for comfort and feeding, only that they should not sleep in the same bed as their parents.

It is also important to be aware that the overall risk of SIDS is very small and it is a rare condition. However, there are simple steps parents can take to reduce the risk of SIDS (see box), and it is well worth following this potentially life-saving advice.


SIDS – reducing the risk

The single most important step you can take to reduce the risk of SIDS is to avoid smoking around your baby.


Other ways of preventing SIDS include:

  • placing your child on their back to sleep
  • never sleeping with your baby on a sofa or an armchair
  • not allowing your baby to get too hot
  • keeping your baby's head uncovered
  • breastfeeding, if possible


Where did the story come from?

The study was carried out by an international team of researchers from the London School of Hygiene and Tropical Medicine, the University of Glasgow and the Medical Research Council, UK; the Children's University Hospital, Ireland; the University of Auckland, New Zealand; and the University of Muenster, Germany.

No external sources of funding were reported, although the original research this report is based on was funded by a number of governmental bodies, charities and trusts.

The study was published in the peer-reviewed open access medical journal, BMJ Open.

The story was well reported by the media. 


What kind of research was this?

This study combined information from individuals in five large case-control studies. These studies had collected data on babies who died from SIDS (cases) and babies of a similar age who were still alive (controls).

The researchers were interested in bed-sharing specifically. The research aimed to resolve the uncertainty over whether there is a risk of SIDS associated with bed-sharing in breastfed babies where neither parent smoked. 


What did the research involve?

The researchers combined individual data from studies in the UK, Europe and Australasia. In total, information was collected for 1,472 babies who died from SIDS and 4,679 control infants, all under one year of age. Control infants were randomly selected normal infants of a similar age, from a similar location and born at a similar time.

The researchers estimated the risk associated with bed-sharing in relation to breastfeeding, smoking, and the mother's recent alcohol consumption or illegal drug use. This was after they had controlled for other important risk predictors, including:

  • whether the baby slept in the parents' room or elsewhere
  • the position in which the baby was put to sleep
  • mother's age
  • mother's relationship status
  • the number of children the mother had had previously
  • the baby's birth weight


What were the basic results?

The researchers found that 22.2% of cases and 9.6% of controls reported a history of bed-sharing. Bed-sharing increased the risk of SIDS fivefold (adjusted odds ratio [OR] 5.1, 95% confidence interval [CI] 2.3 to 11.4) compared with room-sharing (assuming the baby was placed on his or her back in a cot in the parents' room) when:

  • neither parent smoked
  • the mother did not drink
  • the baby was less than three months old
  • the baby was breastfed, and
  • there were no other risk factors

The researchers estimate that the absolute risk of SIDS for room-sharing infants was 0.00008 (eight per 100,000) when neither parent smoked and the baby was less than three months old, breastfed, and had no other risk factors.

Bed-sharing increased the absolute risk of SIDS by 0.15 per 1,000. This means the absolute risk from bed-sharing was 0.00023 (0.23 per 1,000).

Bed-sharing, smoking and alcohol use all increased the risk of SIDS. However, the risks associated with bed-sharing decreased as the baby got older.


How did the researchers interpret the results?

The researchers concluded that, "Bed-sharing for sleep when the parents do not smoke or take alcohol or drugs increases the risk of SIDS. Risks associated with bed-sharing are greatly increased when combined with parental smoking, maternal alcohol consumption and/or drug use. A substantial reduction of SIDS rates could be achieved if parents avoided bed-sharing."



This large case-control study combined information from five studies to investigate the risk of sudden infant death syndrome (SIDS) associated with bed-sharing.

It found that bed-sharing is associated with a fivefold increase in the risk of SIDS compared with room-sharing for babies who were less than three months old, breastfed, sharing with non-smoking parents, and the mother had not had alcohol or drugs.

Smoking, alcohol and drug use are already recognised risk factors for SIDS and greatly increase the risk associated with bed-sharing.

The researchers have not concluded that babies should not be brought into the parents' bed for comfort and feeding. Rather, they advise that babies should not sleep in their parents' bed. It is also worth highlighting the very small actual risk of SIDS, both for non-sharing and bed-sharing babies.

Although this study was appropriately designed and controlled for, a number of potential factors that could affect the risk of SIDS and the causes of SIDS are not firmly established. This means that there may be other factors responsible for the observed increase in risk associated with bed-sharing.

To decrease the risk of SIDS, current advice recommends:

  • putting your baby to sleep on their back – the safest place for them to sleep is in a cot in a room with you for the first six months
  • do not smoke
  • do not share a bed with your baby, particularly if you have been drinking or have taken drugs
  • never sleep with your baby on a sofa
  • do not let your baby get too hot and keep your baby's head uncovered
  • if possible, breastfeed your baby

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Analysis by Bazian

Edited by NHS Choices


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The 4 comments posted are personal views. Any information they give has not been checked and may not be accurate.

chatsubo said on 24 May 2013

Add I appreciate that this article has some criticism, but we did make a conscious effort to highlight some of the limitations of the research, such as there could be a wide range of cofounders contributing towards SIDS risk. So there could be other factors other than bed-sharing, and a direct cause and effect link has not be proven.

I am also happy to highlight the UNICEF advice as suggested.

Best Wishes,
Behind the Headlines

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Essexmum said on 22 May 2013

As this article is on an NHS website if could be interpreted/misinterpreted as an endorsement of the recent SIDS article in the BMJ. You need to be clear that it is NOT.

However, NOT all sleep researchers, NGOs and Breastfeeding organisation agree with the conclusions of this "Analysis" which was based on data 15-26 years old.

Unicef UK's recommendation to health professionals on the key information which should be discussed with all parents to protect babies is outlined in their statement yesterday. (see their website fore more details) in conjunction with the leaflet "Caring for your Baby at night".
Shouldn't you be reporting that?

The researchers at the University of Durham's Infant Sleep Lab and the leading experts in this area have also issues a statement outlining the flaws and holes in this study.
Please could you report on that?

The NCT and the Association of Breastfeeding Mothers also issued statements criticising the BMJ article's methodology. Please could you report this?

NHS Choices needs to report a balanced view and reflect all sides of the article as not all experts agreed.

Japan has one of the lowest rates of SIDS and it is a cultural norm for (non smoking, non drinking) mothers to breastfeed and bedshare with their babies.

"The Impression from the press that infants in the general population are at a 5-fold risk of SIDS when the parents bed-share and don't smoke, which is untrue" (Unicef UK Baby Friendly Initiative Statement 21 May 2013)

The real message which could actually save lives is that "Smoking, Drinking, Taking Drugs/Mediation (legal and illegal) when caring for your baby can increase the risk of SIDS."

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User747717 said on 21 May 2013

Thank you Sarah Ockwellsmith,I co sleep with my three month old and have done so since day one and did so with my other daughter.The above article freaked me out as we are very mindful of how we co sleep. Your comments have reassured me and helped reinforce why we co sleep and will continue to do so. We will ofcourse continue to be aware of risk and reduce risks where possible. We can sleep easy!

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Sarah OckwellSmith said on 21 May 2013

I am appalled that the NHS would post this article without checking the validity and reliability of the research beforehand, if they had this article would never have made it online.

The research has a number of huge flaws which render its findings completely useless, this would not be so bad had it not been so widely reported and used to scare a large number of vulnerable new parents. Key flaws include:

1. Data inclusion 19-20 years old (pre-dating much current advice concerning safer infant sleep)

2. Variables not incuded in the analysis include differentiation between planned and unplanned bedsharing (planned bedsharing has been proven to NOT increase SIDS risks as shown in 2009 research by Vennemann, one of the authors of this current research!), differentiation between exclusive and non-exclusive breastfeeding, 80% missing data concerning maternal alcohol consumption and no data at all on paternal consumption, no data on prematurity and most worryingly of all, no data on prescription medication, which considering infants were all 12 wks or younger would be quite high amongst mothers recovering from birth injuries who are commonly prescribed analgesic opiates. These are all known risk factors.

At best this research is misguided and ill informed, at worst it is dangerous. Research show that 60-80% of parents bring their baby into bed with them at least once, this will not change - only now they will do so in guilty secret with no knowledge of how to keep their baby safe, or perhaps they will fall asleep exhausted on a sofa which is incredibly high risk for SIDS.

The NHS and other policy makers would do well to respect the parenting decisions (often culturally based and many times well researched) made by individuals and provide them with unbiased, factually correct information so that they may make an INFORMED CHOICE for what is best for their families to keep their baby as safe as possible.

Shame on you for not doing so here!

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