London Child Safety Update – Sudden Unexpected Deaths in Infancy: Advice for people working with children, young people and families


  • to summarise the evidence about sudden unexpected deaths in infancy (SUDI)
  • to develop an evidence-based resource about prevention of SUDI that can be shared with key stakeholders

Key facts about sudden unexpected deaths in infancy:

  • SUDI is the sudden and unexpected death of an infant under the age of one year that remains unexplained after thorough investigation. It is the leading cause of death between one month and one year of age
  • in 2012 across England and Wales, there were 221 unexplained infant deaths, eight out of 10 of these unexplained deaths occurred in the post-neonatal period (after 28 days)
  • In London:
    • every 11 days a baby died unexpectedly
    • in 2012 the number of unexplained infant deaths has fallen by about 23% from 2005 (44 deaths) to 2012 (34 deaths)

There is a wide variation of unexplained infant deaths across London: between 2005 and 2012 only seven out of the 32 London boroughs witnessed more than 15 unexpected infant deaths.

Risk factors for sudden unexpected death in infancy

AgeBabies under the age of one year are most at risk and
being a younger mother is associated with a higher of
Birth weightRates of SUDI are higher in low birth weight babies (less
than 2,500g (5lb 5oz))
PovertyDeprivation has been linked to the occurrence of SUDI
and higher risk is observed when infants are within
families of a lower socioeconomic group
PrematurityBabies born preterm (less than 37 weeks gestation) are at four times the risk compared to babies born at term
SmokingBabies are at greater risk when a mother smokes during
pregnancy or if there is smoking in the home. An
estimated one-third of SUDI deaths could be prevented if
mothers did not smoke in pregnancy
Sleeping habitsGreater risk is associated with placing a baby on the front or side to sleep or in a room alone. Bed sharing with a baby when a parent is a smoker or under the influence of
drugs or alcohol may also increase risk. Overcrowding
has been identified as a factor affecting sleeping habits in
the home. Unexpected infant deaths are also associated
with overheating; overwrapping the baby or placing objects in the cot may increase heat

Most babies (91%) who die from SUDI have one or more risk factor present, 75% have two or more risk factors present.

Actions to prevent sudden unexpected death in infancy:

  • early (antenatal) education of carers and parents on ‘safer sleeping actions’, including:
    • ensuring that infants sleep in the supine position – ‘back to sleep’
    • keeping the baby’s head uncovered by placing the baby in the ‘feet to foot’ position
    • ensuring that infants sleep in a separate cot
    • ensuring that infants sleep in the same room as their parents
    • avoid sleeping on sofa with infant
  • reducing smoking in pregnancy and parents and exposure to tobacco smoke in the home and cars
  • encouraging and supporting mothers to breastfeed
  • focusing prevention programmes on families most at risk, in particular those with social circumstances that expose infants to more risk and promote parental behaviour change
  • training carers and parents in rescue and resuscitation techniques to minimise the severity of outcomes from accidents
  • local areas should be encouraged to review current practices and address any gaps ensuring:
    • leadership for effective implementation of multiagency protocols
    • intra-agency accountability and mechanisms for information sharing to minimise risk
    • provision of training for all staff in contact with families
    • awareness raising and education about SUDI using available resources and by disseminating learning from investigated cases across all agencies and stakeholders
    • provision of adequate support to affected parents and families


We are grateful to the following:
Alison Burton, maternity and early years lead, Public Health England
Professor Viv Bennett, director of nursing, Public Health England
Sheena Carr, senior public health commissioner, children and young people, London Borough of Haringey
Dr Justin Daniels, consultant paediatrician, North Middlesex Hospital NHS Trust
Dr Jide Menakaya, consultant paediatrician, Hillingdon Hospital NHS Foundation Trust
DCI Michael Orchard, Operation Yewtree and major investigations, Metropolitan Police
Cheryl Pearce, regional development officer for London, Lullaby Trust
Louise Soler, head of communications, Lullaby Trust
DC Sarah Wood, partnership team sexual offences, exploitation and child abuse investigation command, Metropolitan Police

PHE London contacts:
Dr Marilena Korkodilos:
Modupe Omonijo:


  • Carpenter R et al 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 2013; 3:e002299 doi:10.1136/bmjopen-2012-002299
  • Child Death Review Programme and All Wales Perinatal Survey (2015) Sudden Unexpected Death in Infancy – A Collaborative Thematic Review 2010-2012
  • Horn R, Hauk F, Moon R BMJ 2015; 350: h1989 Sudden infant death syndrome and advice for safe sleeping
  • Livesey A BMJ 2005; 330:227 A multiagency protocol for responding to sudden 27 January 2005)
  • Project Indigo (2014) Sudden unexpected death in infancy: Analytical report June 2013
  • NICE (2014) Clinical guideline 37, Postnatal care,
  • ONS (2014) Statistical bulletin: Unexplained deaths in infancy – England and Wales, 2012
  • Weightman AL, Morgan HE, Shepherd MA, et al. Social inequality and infant health in the UK: systematic review and meta-analyses BMJ Open 2012;
  • 2:e000964. doi:10. 1136/bmjopen-2012- 00964