Sudden infant death syndrome (SIDS) is the sudden and unexplained death of an infant where no cause is found after detailed post mortem.

  • 168 unexplained infant deaths occurred in the entire UK in 2020, a rate of 0.25 deaths per 1,000 live births
  • 150 unexplained infant deaths occurred in England and Wales in 2020, a rate of 0.24 deaths per 1,000 live births: a decrease from 0.29 deaths per 1,000 live births in 2019
  • Over half (63%) of all unexplained infant deaths were boys in 2020 (0.30 deaths per 1,000 live births). This is an increase from 57% in 2019
  • In 2020, the unexplained infant mortality rate was highest for mothers aged under 20 years, at 1.07 deaths per 1,000 live births. This is over seven times higher than for mothers aged 30 to 34 years who had the lowest rates

Credit: Office of National Statistics, National Records of Scotland and Northern Ireland Statistics and Research Agency 2020

*England and Wales data includes International Classification of Diseases (ICD) codes R95 (Sudden Infant Death Syndrome) and R99 (Ill Defined/Unknown), Northern Ireland data includes ICD code R95, R96 and R99 and Scotland data includes ICD code R95 only.*