Babies can lose heat quickly if they're left in a cold room because they can't regulate their body temperature as well as older children and adults. Newborn babies in particular are at risk for the first 12 hours of their life.
In some cases, medical professionals may deliberately make someone develop hypothermia as a treatment. This is known as therapeutic hypothermia. There's evidence to suggest that, in some circumstances, inducing a state of hypothermia in the body can reduce the risk of death and increase the chances of a good recovery.
I picked the NHS site because it is very reliable and has been studied by professional scientist and doctors and there results have been proven to be right
http://www.nhs.uk/Conditions/Hypothermia/Pages/Causes.aspx