Newborns that have particular problems in producing enough heat in their bodies, or who lose too much heat because of poor care by the mother, are at the greatest risk.

Newborns who may not produce enough heat include those who are:

• Preterm
• Underweight for gestational age
• Wasted (thin)
• Infected
• Hypoxic (starved of oxygen during labour and delivery).

Newborns that lose too much heat include those who are:

• Wet after washing, or left in wet clothes
• Have not been fed enough
• Exposed to a cold environment, not enough clothes or covers, especially when they are sleeping
• Naked when they are breastfed
• Fed close to a cold window, in a draught of cold air.