Toddler waking through the night?

Question

I have an 18 month old toddler who has taken to waking up at 3 - 4 am over the last couple of weeks, for no apparent reason. She cries, with her dummy still in her mouth. When I go in there she stops crying as soon as she hears the door open, but doesn't seem to actually wake up (open her eyes at least) She will generally go back to sleep for 20 minute intervals until I finally let her out of her room at about 6.

I have tried a big filling dinner, a small dinner, bottle of milk, nappy is always changed before bed, she has a nightlight, she has a sensible bedtime 6pm (I have tried putting her to bed later, makes no difference) she has no new teeth coming through, she isn't sick, she is comfortably warm, she has a good bedtime routine (bath, dinner, book, bottle, brush teeth, bed) The frustrating part is that I haven't changed a thing, and my Toddler who has slept through from 8 weeks has decided to wake at 4am.

Answer 1

She may be having night terrors or nightmares.  

Answer 2

check out info on nightmares and night terrors- she's probably too young for night terrors, but it's still possible.

If there's been any change in routine or something traumatic, that could be it