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My 12 month old has been waking at 4-4:30 am for quite some time. He usually doesn't require anything to go back to sleep but just wakes crying and grizzly. Sometimes I go in and give him his dummy other times he still has his dummy so I just lay him back down and he goes back to sleep until about 7am. I cannot work out why he is waking at this time and how to get him to just sleep through.