Co-Sleeping: An Evidence-Based Perspective

Few parenting topics create as much confusion, judgement and anxiety as where babies should sleep. As a doula, I regularly support families who are exhausted, overwhelmed, and unsure whether co-sleeping is “safe”, “normal”, or somehow harmful in the long term.

This post explores what the evidence actually says about co-sleeping, including bed-sharing and room-sharing, from a UK context. My aim is not to prescribe one approach, but to empower families with clear, compassionate, research-based information so they can make informed choices.

What Do We Mean by Co-Sleeping?

Co-sleeping is an umbrella term that includes:

• Room-sharing: baby sleeps in a cot, Moses basket or sidecar in the same room as their caregiver.

• Bed-sharing: baby sleeps on the same sleep surface as a parent.

Both arrangements are biologically normal in many cultures, yet often poorly explained within Western healthcare frameworks.

Why Babies Seek Closeness at Night

Human infants are born neurologically immature and highly dependent on caregivers for regulation. Proximity to a parent supports:

• Physiological regulation (breathing, temperature and heart rate)

• Stress reduction, through sensory input such as touch, scent and voice

• Attachment formation, which develops through consistent, responsive care

Research demonstrates that close physical contact between mother and infant supports co-regulation of breathing and arousal patterns, particularly during sleep (McKenna and Gettler, 2016).

From a developmental perspective, waking frequently and seeking contact is not a “problem” to be trained out, it is part of normal infant biology.

Co-Sleeping and Breastfeeding

One of the most consistent findings in infant sleep research is the association between proximity at night and breastfeeding outcomes.

Studies show that:

• Room-sharing and safe bed-sharing are linked to more frequent feeds

• Night-time access supports milk supply and longer breastfeeding duration

• Mothers often experience greater ease of feeding when their baby is nearby

Ball et al. (2019) found that bed-sharing breastfeeding dyads naturally adopt protective sleep positions that facilitate frequent feeding while maintaining infant airway visibility. This has important implications for both infant nutrition and maternal rest.

Does Co-Sleeping Create “Dependency”?

There is no evidence that responding to infants at night leads to long-term dependency, emotional insecurity, or poor sleep in later childhood.

In fact, attachment research suggests the opposite: children whose needs are met consistently in infancy are more likely to develop secure attachment, emotional regulation and independence over time (Bowlby, 1988; Sroufe et al., 2005).

Night-time care is not separate from day-time parenting. Babies do not learn independence through unmet needs they learn safety through responsiveness.

Understanding the Risks: When Co-Sleeping Is Not Safe

While co-sleeping can be nurturing, evidence also clearly shows that certain factors significantly increase risk, particularly in bed-sharing contexts.

According to UK research and public health guidance, risk is higher when bed-sharing occurs alongside:

• Smoking (during pregnancy or after birth)

• Alcohol or drug use (including prescription sedatives)

• Sofas or armchairs (high risk of suffocation)

• Soft mattresses, heavy bedding or pillows near the baby

• Premature birth or low birth weight

Large-scale studies in the UK have demonstrated that bed-sharing in hazardous circumstances is strongly associated with increased risk of sudden infant death (Blair et al., 2014).

However, it is equally important to note that planned bed-sharing in the absence of these risk factors shows a very different risk profile (Blair et al., 2014; McKenna and Gettler, 2016).

Safer Co-Sleeping: A Harm Reduction Approach

Many families, intentionally or unintentionally, will share sleep at some point, often during feeding, illness, or extreme exhaustion. For this reason, organisations such as UNICEF UK Baby Friendly and researchers in infant sleep increasingly advocate for a harm-reduction model rather than blanket prohibition.

Safer bed-sharing guidance generally includes:

• A firm, flat mattress

• No smoking, alcohol or drugs

• Baby placed on their back

• Light bedding kept well away from the baby

• No other adults or pets in the bed

• Never on a sofa or armchair

Providing families with realistic, evidence-based guidance helps reduce risk far more effectively than telling parents “never do it”, particularly when sleep deprivation is a known factor in accidents.

A Doula’s Perspective: Informed Choice, Not Fear

As a doula, my role is not to tell families how they should sleep. It is to ensure they understand:

• Their baby’s biological needs

• The evidence around safety and risk

• The options available to them

Some families choose room-sharing in a cot. Some choose bed-sharing with careful safety measures. Others use sidecar cribs or respond flexibly through the night. All of these can be valid when rooted in knowledge, safety and responsiveness.

What families do not need is fear-based messaging that ignores real-world parenting, cultural context, mental health and breastfeeding support.

Final Thoughts

Co-sleeping is neither inherently dangerous nor automatically safe - it is context-dependent. When approached with evidence, care and attention to safety, close night-time parenting can be a nurturing, biologically aligned way to support both infant wellbeing and parental rest.

If you are navigating sleep with your baby and would like personalised, non-judgemental support, I am here to help. Contact Me below:

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References

Ball, H.L., Ward-Platt, M.P., Howel, D., Russell, C., Kennedy, A.R. and Blair, P.S. (2019) ‘Randomised trial of side-car crib use on breastfeeding duration (NECOT study)’, Archives of Disease in Childhood, 104(3), pp. 233–239.

Blair, P.S., Sidebotham, P., Pease, A. and Fleming, P.J. (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’, PLOS ONE, 9(9), e107799.

Bowlby, J. (1988) A Secure Base: Parent-Child Attachment and Healthy Human Development. London: Routledge.

McKenna, J.J. and Gettler, L.T. (2016) ‘There is no such thing as infant sleep, there is infant–parent sleep: an anthropological perspective on normal infant sleep development’, in McKenna, J.J. (ed.) Sleeping with Your Baby: A Parent’s Guide to Co-Sleeping. Revised edn. London: Pinter & Martin, pp. 43–63.

Sroufe, L.A., Egeland, B., Carlson, E. and Collins, W.A. (2005) The Development of the Person: The Minnesota Study of Risk and Adaptation from Birth to Adulthood. New York: Guilford Press.

UNICEF UK Baby Friendly Initiative (2021) Caring for your baby at night. Available at: https://www.unicef.org.uk/babyfriendly (Accessed: 02/02/26).

The Lullaby Trust (2023) Safer sleep advice for parents. Available at: https://www.lullabytrust.org.uk (Accessed: 02/02/26).