Some autopsy data shows that infants of smokers have signs of established hypoxic - ischemic
cellular injury in the brain and the heart which probably occurred in antenatal
life, may have been caused by suboptimal placental function and may have been sub-clinical, but if the baby continues to be in a vulnerable environment exposed to post-natal passive smoking, this could
affect autonomic nervous system function and lead to poor temperature control, and poor heart rate and respiration control.