There is no absolute relationship between a one year old baby not sleeping all day, or not getting enough sleep, and a fever, and it doesn’t necessarily cause a fever. However, it may also be related to infections such as viruses and bacteria, which may then cause a fever. Fever needs prompt medical attention. The baby did not sleep a day or lack of sleep, there may be fatigue, poor mental state, etc., did not sleep and fever is not too related, not necessarily cause a fever. If a one-year-old baby hasn’t slept for a day, it is caused by an illness caused by a viral or bacterial infection, which may cause a fever. Or if the baby has Kawasaki disease or a blood disorder, it may also cause a fever. All in all there are many possible reasons why a one year old baby does not sleep for a day, and they may not always cause fever. If your baby has a fever, he or she should go to the pediatric department of the hospital in time for examination, and can be professionally handled and treated under the guidance of the doctor.