Sudden infant death syndrome

Sudden infant death syndrome is the commonest cause of death in the first year of life. It is most common at 3 months of age.

Major risk factors

• putting the baby to sleep prone: the relative risk or odds ratio varies from 3.5 - 9.3. If not accustomed to prone sleeping (i.e. the baby usually sleeps on their back) the odds ratio increases to 8.7-45.4
• parental smoking: studies suggest this increases the risk up to 5 fold
• prematurity: 4-fold increased risk
• bed sharing: odds ratio 5.1
• hyperthermia (e.g. over-wrapping) or head covering (e.g. blanket accidentally moves)

Other risk factors

• male sex
• multiple births
• social classes IV and V
• maternal drug use
• incidence increases in winter

It is important to remember that these odds are additive. For example, if both parents smoke, the mother had consumed two units of alcohol and they then shared a bed with the infant the adjusted odds ratio was shown to be 89.7.

Protective factors

• breastfeeding
• room sharing (but not bed sharing, which is a significant risk factor)
• the use of dummies (pacifiers)

Following a cot death siblings should be screened for potential sepsis and inborn errors of metabolism.