Folks coming to my site from Google use the most interesting keywords. In the interest of answering the keywords, here is the search criteria and then my answer.
baby without oxygen 12 minutes
How was this baby without oxygen for 12 minutes? Inside? Outside? The baby would not be alive if it was without oxygen for 12 minutes. If they were resuscitating for 12 minutes, then the baby is receiving oxygen, just not breathing it themselves.
This site (click #3) speaks about serious damage occuring after 3 minutes, unlikely to recover after 10 and recovery vitually impossible after 15.
However, this does not speak of a newborn who has not received oxygen except through his/her mother's blood stream. If the baby was compromised inside as well, the baby not breathing outside will begin with a deficit of oxygen to the brain.
My heart goes out to whomever asked this question. 12 minutes must have been horrifyingly scary. I pray the baby was being resuscitated and not just laying there without someone helping.