Bed Sharing, Infant Sleep and SIDS

Research on infant health

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The latest bed-sharing research is outlined here. For guidance on discussing co-sleeping with parents, read our Co-Sleeping and SIDS: A Guide for Health Professionals leaflet.

Safer sleep guidance for maternity healthcare professionals

This guidance by the Royal College of Midwives shares key messages on safer sleep and advocates for clear and tailored advice on how to reduce  Sudden Unexpected Death in Infancy (SUDI) to be given to all carers and maternity support workers. It includes information about the importance of a clear, flat, uncluttered sleeping space for the baby in their parents’ bedroom; information about how to avoid overheating and about the risks of ‘overlying’ when sharing a sleep space with a baby, particularly when sharing a sofa.

Royal College of Midwives. 2021. Safer sleep guidance for maternity healthcare professionals

Baby-box schemes in England: parent and practitioner experiences, and recommendations

This 2020 study concludes that whilst many assumptions exist about the origins and purpose of baby-boxes; this misinformation needs correcting, especially as it relates to infant death reduction and safe infant sleep. Baby-box schemes take multiple forms from those motivated by social welfare to those motivated by commercial profit. The English experience of partnership schemes between healthcare facilities and commercial box-providers reveals some success stories, along with multiple points of ambiguity, unanticipated difficulty, and concerns for infant safety.

Ball, H.L., Taylor, C.E. Baby-box schemes in England: parent and practitioner experiences, and recommendations. BMC Pediatr 20, 154 (2020).

Trends in Breastfeeding Interventions, Skin-to-Skin Care, and Sudden Infant Death in the First 6 Days after Birth

This study aimed to determine if the implementation of skin-to-skin care and the Baby-Friendly Hospital Initiative (BFHI) contribute to sudden unexpected infant death (SUID) and asphyxia in the first 6 days after birth. Findings were based on data from the Centers for Disease Control and Prevention (CDC), CDC WONDER and the Massachusetts Department of Public Health. Data related to the implementation of BFHI from 2004-2016, rates of skin-to-skin from 2007-2015 and rates of SUID and asphyxia from 2004-2016 were used, allowing researchers to find a temporal association between the increase of breastfeeding initiatives and skin-to-skin care with the decreasing occurrence of SUID. This study took place in America but has relevance in the UK.

Melissa B. MD, MSc, FABM. et al (2019). Trends in Breastfeeding Interventions, Skin-to-Skin Care and Sudden Infant Death in the First 6 Days after Birth. Revision 2019. 

Bedsharing and Breastfeeding: The Academy of Breastfeeding Medicine Protocol 

New guidelines for health professionals released by the Academy of Breastfeeding Medicine explored safe bedsharing for infants who are being breastfed. The authors call for a greater discussion on the evidence-based benefits and risks of both bedsharing and separate sleeping in the postnatal period, warning that accidental bedsharing can ultimately be more dangerous than when conducted intentionally in a safe environment. This is an American protocol but has relevance in the UK. Recommendations highlight that health professionals must take into account the mothers’ knowledge, beliefs and preferences and acknowledge the known benefits and risks of bedsharing.

Peter S. et al (2019). Bedsharing and Breastfeeding: The Academy of Breastfeeding Medicine Protocol #6, Revision 2019

An Integrated Analysis of Maternal-Infant Sleep, Breastfeeding, and Sudden Infant Death Syndrome Research Supporting a Balanced Discourse

This integrated analysis reviewed research on breastfeeding and maternal and infant sleep, considering where we are in safeguarding both infant lives and breastfeeding, and how to improve our knowledge and inform policy and practice. The authors found that many breastfeeding mothers and caregivers do sleep with their infants whether intentionally or unintentionally. They argue that the data supports policies to counsel parents and caregivers on safe sleep practices, including bed-sharing in non-hazardous circumstances, particularly in the absence of parental smoking, recent parental alcohol consumption, or sleeping next to an adult on a sofa. Further research with appropriate methodology is needed to drill down on actual rates of infant deaths, paying close attention to the definitions of deaths, the circumstances of the deaths, and confounding factors, in order to ensure we have the best information with which to derive public health policy. Introduction and use of the concept of “breastsleeping” is a plausible way to remove the negative connotations of “co-sleeping” and redirect ongoing data-driven discussions and education of best practices of breastfeeding and sleep.

Marinelli, K, Ball, H, McKenna, J, and Blair, P, (2019). An Integrated Analysis of Maternal-Infant Sleep, Breastfeeding, and Sudden Infant Death Syndrome Research Supporting a Balanced Discourse, Journal of Human Lactation,

The Atlantic Divide: Contrasting U.K. and U.S. Recommendations on Cosleeping and Bed-Sharing

This Insights in Practice explores the current state of guidance regarding sudden infant death syndrome (SIDS) and cosleeping or bed-sharing in the United Kingdom and United States. The goal is to help lactation professionals and allied staff become aware of the larger contextual picture on this topic and to encourage reflection on how we educate new parents around infant sleep location. It explores how over the past 2 to 3 years, the nature and content of discussions on this topic have begun to shift, and agreements are emerging.

Ball, H, (2017). The Atlantic Divide: Contrasting U.K. and U.S. Recommendations on Cosleeping and Bed-Sharing, Journal of Human Lactation,

Duration of Breastfeeding and Risk of SIDS: An Individual Participant Data Meta-analysis

This review of 2,267 SIDS cases and 6,837 control infants explored the duration of breastfeeding required to confer a protective effect against Sudden Infant Death Syndrome (SIDS). It found that any breastfeeding for at least two months was associated with half the risk of SIDS. Greater protection was seen with increased duration, both with exclusive and any breastfeeding.

Thompson, JMD, et al (2017), Duration of Breastfeeding and Risk of SIDS: An Individual Participant Data Meta-analysis. Pediatrics, doi: 10.1542/peds.2017-1324

Who bed-shares and what is the relationship with breastfeeding duration?

This study explored the link between breastfeeding duration and bed-sharing frequency among women reporting a prenatal intention to breastfeed.

It was found that women with strong motivation to breastfeed frequently bed-share. The authors note that, given the complex relationship between bed-sharing and sudden infant death syndrome (SIDS), appropriate guidance balancing risk minimisation with support for breastfeeding mothers is crucial.

Ball, H. L. et al (2016). Bed-sharing by breastfeeding mothers: who bed-shares and what is the relationship with breastfeeding duration? Acta Paediatrica, DOI: 10.1111/apa.13354.

SIDS and infant sleep ecology

In this article, the authors looked at Sudden Infant Death Syndrome (SIDS) from an evolutionary perspective. Comparative evolutionary studies indicate that human infants are poorly neurologically developed at birth, and thus require close physical contact for safety, physiological regulation and frequent feeding. The authors argue that species-specific sleep ecology involves close contact with a carer and frequent sleep arousals for the first 6 months of life.

The authors conclude that a more holistic view of infant sleep ecology is warranted, in order for clinicians to encourage parental proximity and responsive care, and educate parents about infant developmental needs.

Ball & Russell (2014), SIDS and infant sleep ecology. Evolution, Medicine and Public Health 146. doi: 10.1093/emph/eou023

Bed-sharing in the absence of hazardous circumstances

This study examined 400 cases of SIDS against 1386 comparable controls. Researchers found that the incidence of co-sleeping among the SIDS infants was significantly higher than for the controls. However when results were broken down to specific co-sleeping environments, it was found that co-sleeping on a sofa, or next to a parent who had drunk more than two units of alcohol carried a very high risk. Co-sleeping next to a smoker was significant for infants under three months, whilst the risk associated with bed-sharing in the absence of these factors was not significant overall, and was in the direction of protection for older infants (over three months).

The authors argue that public health strategy should therefore focus on making parents aware of specific hazardous co-sleeping environments to avoid: sofa-sharing, alcohol, drugs, smoking, or co-sleeping if the infant is pre-term.

Blair, P. S. et al (2014) Bed-Sharing in the Absence of Hazardous Circumstances: Is There a Risk of Sudden Infant Death Syndrome? An Analysis from Two Case-Control Studies Conducted in the UK. DOI: 10.1371/journal.pone.0107799

Unicef UK Baby Friendly Initiative statement on bed-sharing research

Read our statement in response to a 2013 study on bed-sharing and SIDS (pdf download): Carpenter R, McGarvey C, Mitchell EA et al. (2013) Bed sharing when parents do not smoke: is there a risk of SIDS? An individual level analysis of five major case-control studies. BMJ Open. doi:10.1136/bmjopen-2012-002299

Infant care practices related to SIDS in South Asian and White British families

This is by far the largest comparative study of ethnic differences in infant care in the UK to date, and the size of the sample is a major strength. The researchers report that South Asian infant care practices were more likely to protect infants from the most important SIDS risks such as smoking, alcohol consumption, sofa-sharing and solitary sleep. These differences may explain the lower rate of SIDS in this population and this study identifies these issues as clear targets for SIDS risk reduction among White British families.

Ball HL, Moya E, Fairley L et al (2011) Infant care practices related to sudden infant death syndrome in South Asian and White British families in the UK. Paediatric and Perinatal Epidemiology. DOI: 10.1111/j.1365-3016.2011.01217.x

Does sidecar crib use affect breastfeeding duration?

A randomised trial of 1,204 pregnant women intending to breastfeed was carried out at the Royal Victoria Infirmary in Newcastle to determine whether the use of sidecar cribs on the postnatal wards affected breastfeeding duration. The authors conclude that the use of sidecar cribs does not affect breastfeeding duration or rates of exclusive breastfeeding or the frequency of bed-sharing once home.

Helen L Ball, Martin P Ward-Platt, Denise Howel, Charlotte Russell (2011). Randomised trial of sidecar crib use on breastfeeding duration (NECOT). Arch Dis Child, doi:10.1136/adc.2010.205344.

Relationship between bed-sharing and breastfeeding: This study investigated nocturnal bed-sharing of 14,062 live births at 5 time points from birth to 4 years of age.

The researchers identified 4 mutually exclusive groups, broadly described as nonsharers (66%), early bed sharers (only in infancy) (13%), late bed sharers (after the first year) (15%), and constant bed sharers (throughout the 4 years) (6%). The boy/girl ratio and the proportion of families of nonwhite ethnicity were slightly higher in all 3 bed-sharing groups, compared with the non–bed-sharing group. Higher maternal educational achievement and higher social class were positively associated with early bed sharing, negatively associated with late bed sharing, and not associated with constant bed sharing. The 3 bed-sharing patterns were related significantly to breastfeeding at 12 months. The prevalence of breastfeeding was significantly higher among the groups that shared beds constantly or early for each of the first 15 months after birth.

The authors state it is difficult to be precise about the dominant direction of the relationship between bed-sharing and breastfeeding, whether mothers share beds because they are breastfeeding or whether bed-sharing makes breastfeeding more likely to be successful. They conclude that risk reduction messages to prevent sudden infant deaths should be targeted more appropriately to unsafe infant care practices such as sleeping on sofas, bed-sharing after the use of alcohol or drugs, or bed-sharing by parents who smoke, and that advice on whether bed-sharing should be discouraged needs to take into account the important relationship with breastfeeding.

Relationship Between Bed Sharing and Breastfeeding: Longitudinal, Population-Based Analysis. Peter S. Blair, Jon Heron, and Peter J. Fleming; Pediatrics. published online 18 October 2010, 10.1542/peds.2010-1277.

Breastfeeding to help babies sleep

Researchers found that concentrations of the three nucleotides most strongly associated with sleep and sedation (5’UMP, 5’AMP and 5”GMP) varied according to time of day. Concentrations of 5’AMP were highest at the beginning of the night, while levels of 5’GMP and 5’UMP increased as the night wore on. These sedatives were found at much lower concentrations in milk expressed during the day.

Nutritional Neuroscience, DOI: 10.1179/147683008X344174; Neuroendocrinology Letters, vol 28, p 360

Link between alcohol or drug use and increased risk of SIDS

This study investigated the factors associated with sudden infant death syndrome (SIDS) in 80 infants and two control groups. They found that many of the deaths in a co-sleeping environment could be explained by a significant interaction between co-sleeping and recent parental use of alcohol or drugs (31 per cent vs 3 per cent random controls) and the increased proportion of SIDS infants who had co-slept on a sofa (17 per cent vs 1 per cent).With regard to the infant’s sleeping environment, the authors conclude that the major influences on risk were from factors which would be amenable to change. Parents need to be advised never to put themselves in a situation where they might fall asleep with a young infant on a sofa and that they should never co-sleep with an infant in any environment if they have consumed alcohol or taken drugs.

Blair PS, Sidebo P, Evason-Coombe C et al (2009) Hazardous co-sleeping environments and risk factors amenable to change: case-control study of SIDS in south west England. BMJ; 339:b3666

Does breastfeeding reduce the risk of SIDS?

The German Study of Sudden Infant Death is a case-control study of 333 infants who died of SIDS. The authors say this study shows that breastfeeding reduced the risk of sudden infant death syndrome by around 50% at all ages throughout infancy and for as long as the infant is breastfed. They highlight that the implication of their findings is that breastfeeding should be continued until the infant is six months of age as the risks of SIDS are low by that stage. They therefore recommend including the advice to breastfeed through six months of age in sudden infant death syndrome risk-reduction messages.

M M Vennemann, T Bajanowski, B Brinkmann, G Jorch, K Yücesan, C Sauerland, E A Mitchell and the GeSID Study Group (2009) Does Breastfeeding Reduce the Risk of Sudden Infant Death Syndrome? PEDIATRICS Vol. 123 No. 3 March 2009, pp. e406-e410

Benefits and harms associated with bed-sharing

A systematic review of the literature concludes that the evidence consistently suggests an association between bed sharing and SIDS among smokers, with the evidence not consistent for non-smokers. The evidence also suggests that bed sharing may be more strongly associated with SIDS for younger infants. The review identified a positive association between bed sharing and an increase in the rate and duration of breastfeeding. It is interesting to note that the study defined bed sharing as the practice of sharing a sleep surface and did not therefore identify those cases when the baby was asleep with a parent on a sofa.

Horsley T et al. (2007) Benefits and harms associated with the practice of bed sharing. Arch Pediatr Adolecs Med; 161 (3): 237-245

Mother and infant co-sleeping:

A review of the evidence relating to the sleep practices of parents and infants over the last 20 years provides interesting reading and challenges normal wisdom related to infant sleep. The authors examine the historical and evolutionary background to assess mother and infant shared sleep, especially with regard to the impact on breastfeeding and the reduction of SIDS.

McKenna JJ et al. (2007) Mother-infant cosleeping, breastfeeding and sudden infant death syndrome: what biological anthropology has discovered about normal infant sleep and paediatric sleep medicine. American Journal of Physical Anthropology; 50: 1

Breastfeeding and bed-sharing in England

This study of 1,356 infants found that almost half of all neonates bed-shared at some time with their parents and that on any one night in the first month over a quarter of parents slept with their baby. Breastfeeding was strongly associated with bed-sharing, both at birth and at 3 months.

Blair PS and Ball HL (2004). The prevalence and characteristics associated with parent-infant bed-sharing in England. Arch Dis Child 89:1106-1110

Attitudes and experiences of bed-sharing in Northeast England

This year-long study found that parents pursued a heterogeneous array of night-time parenting strategies and that 65 per cent of the sample had actually bed-shared. Parents with no previous intention to do so slept with their babies for a variety of reasons. Ninety-five per cent of the bed-sharing infants slept with both mother and father. Breastfeeding was significantly associated with co-sleeping.

Hooker E, Ball HL, Kelly PJ (2001). Sleeping like a baby: attitudes and experiences of bedsharing in northeast England.Med Anthropol 19: 203-222.

Similar findings were observed in this study: Ball HL, Hooker E, Kelly PJ (1999). Where will the baby sleep? Attitudes and practices of new and experienced parents regarding co-sleeping with their newborn infants. American Anthropologist 101: 143-51.

Further resources

Co-sleeping and SIDS: A Guide for Health Professionals

Read more

Call to Action on infant feeding in the UK

Read more