My 17 month old son has always been a great sleeper. Very lucky that he slept through from 10 weeks and very rarely wakes now.
He goes to sleep at 7pm without a peep and used to sleep until about 6.30-7am but has now begun waking earlier and earlier (now about 5.30am on average). He's not crying as such but sort of wailing. When I go in he's still lying down in sleep position. I've tried stroking his head gently and saying "Go to sleep" which usually quietens him for 10 minutes until he starts again. Leaving him doesn't work either cause he just gets louder and has continued for over an hour!
He has one daytime nap in the afternoon of between 1-2.5 hours but this doesn't affect his waking in anyway - always early!
It is unrealistic to expect him to sleep longer? I'm just concerned as I have another due in 11 weeks and am desperate for as much sleep as possible!