What does the research say about cosleeping safely?

Specific hazardous conditions dramatically elevate sleep-related infant death risk during cosleeping. Sofa or armchair sharing carries the highest documented risk (OR ~18). Bedsharing with a parent who smokes carries very high risk, particularly for infants under 3 months (OR ~9). Bedsharing after parental alcohol consumption of more than two units also carries very high risk (OR ~18). Supine positioning, firm sleep surfaces, room-sharing without bedsharing, avoidance of soft bedding, breastfeeding, pacifier use, and avoidance of nicotine and alcohol are consistently supported risk-reduction strategies across major guidelines.

Contested

The absolute risk of bedsharing in the absence of all identified hazards (no smoking, no alcohol or drug use, no sofa, term infant, no prone positioning) is debated. One large case-control analysis found no statistically significant SIDS elevation for bedsharing without hazards overall (OR 1.1, 95% CI 0.6-2.0), and a direction toward protection for infants over 3 months. The American Academy of Pediatrics nonetheless recommends against bedsharing in all circumstances, citing residual risk and suffocation hazard. Some researchers argue blanket anti-bedsharing messaging may undermine breastfeeding without proportionate safety benefit, and advocate instead for hazard-specific counseling. The concept of 'breastsleeping' has been proposed to distinguish low-hazard nursing bedsharing from higher-risk arrangements.

What is debated: Whether bedsharing by non-smoking, sober parents with a healthy term infant over 3 months poses meaningful incremental risk, and whether universal bedsharing prohibition is the most effective or appropriate public health message.

What This Means

The evidence points to specific, modifiable hazards rather than cosleeping as a uniform category. Parents and caregivers can act on the following: never share a sofa, armchair, or recliner with an infant during sleep; do not bedshare after consuming any alcohol or sedating medication; do not bedshare if any adult in the bed smokes, even if not smoking at that moment; keep soft bedding, pillows, and loose items away from the infant; place infants on their back on a firm surface. Room-sharing with a separate firm sleep surface is consistently associated with lower risk than both isolated room sleep and bedsharing. Breastfeeding and pacifier use are associated with reduced SIDS risk and are compatible with room-sharing arrangements. Parents who choose to or unintentionally fall asleep feeding an infant should be aware that a firm floor or mattress is substantially safer than a sofa. Families should discuss their specific circumstances and risk profile with a pediatric provider rather than applying a single rule without context.

Receipts

• 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 (2014)
  Cited 194 times

  Combined analysis of two UK case-control studies quantifies risk by specific hazard type; finds no significant elevation for bedsharing in the absence of smoking, alcohol, sofa, or prematurity, and provides the OR estimates most frequently cited in the debate over low-hazard bedsharing.

• Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment (2022)
  Cited 257 times

  The most current AAP policy statement (2022) consolidates safe sleep recommendations, explicitly addresses bedsharing, substance use, and non-inclined surfaces, and includes guidance for clinicians on assessing risk in specific bedsharing situations.

• SIDS and Other Sleep-Related Infant Deaths: Updated 2016 Recommendations for a Safe Infant Sleeping Environment (2016)
  Cited 336 times

  The 2016 AAP update introduced room-sharing without bedsharing as a distinct recommendation and added evidence on bedside sleepers and sofa/armchair risk.

• An Integrated Analysis of Maternal-Infant Sleep, Breastfeeding, and Sudden Infant Death Syndrome Research Supporting a Balanced Discourse (2019)
  Cited 56 times

  Integrated review arguing that hazard-specific counseling is more evidence-consistent than universal anti-bedsharing messaging, and introduces the 'breastsleeping' construct to account for the breastfeeding-sleep interaction.

• SIDS and Other Sleep-Related Infant Deaths: Expansion of Recommendations for a Safe Infant Sleeping Environment (2011)
  Cited 738 times

  2011 AAP expansion of safe sleep recommendations beyond SIDS to all sleep-related infant deaths, establishing the framework still used in current guidelines.

• Sudden infant death syndrome prevention (2021)
  Cited 58 times

  Systematic review through 2020 summarizing evidence strength for each prevention strategy; confirms dramatic SIDS declines following back-to-sleep campaigns and identifies remaining modifiable factors.

• Bedsharing and Maternal Smoking in a Population-Based Survey of New Mothers (2005)
  Cited 46 times

  Population-based survey finding that smoking mothers bedshare at the same rate as non-smoking mothers, indicating that the highest-risk subgroup is not receiving or acting on risk messaging.

• Environment of infants during sleep and risk of the sudden infant death syndrome: results of 1993-5 case-control study for confidential inquiry into stillbirths and deaths in infancy (1996)
  Cited 480 times

  Early large case-control study establishing prone and side sleeping risks and the interaction between maternal smoking and bedsharing, foundational to subsequent guideline development.