My LO is 1 next week and quite frankly she's never been a fantastic sleeper! I can count once or twice in memory where she has slept through 7pm-6am. Usually she wakes atleast once, mostly twice and this is generally fine with us because thankfully she can settle herself very well.
We did do CC when she was approximately 6 months old as we had tried everything else, and up til now we have been able to do bottle, and put her in her cot fully awake, no matter if its for naps, at night for bed or during the night and she would fall asleep.
However... for the past week and a half, self settling for naps have been touch and go, she has been ok settling herself for bed at night, but during the night has been horrendous. She will only sleep from 6.30-9pm and the wakings start. No longer can I go in, give a bit of comfort (usually milk) pop her back down and walk out. Now she protests and wails as soon as I put her back in her cot. So I have tried patting her back which works (temporarily) but often she wakes 5-10 minutes later and the whole process starts again. Last night we were awake from 11pm-2.30am because she just wouldnt settle, the only thing that worked was holding her in my arms in her room until she was in the deepest of sleep and then putting her down and ninja'ing out the room.
We have experienced I think every regression there is and something is telling me that this is another one, but I just cant possibly spend 2-3 hours a night trying to get her to sleep.
She has a dummy attached to her sleeping bag She has a comfort blanket she sleeps on She may be teething so I give calpol if it seems apparent She eats brilliant all day, so I dont think its hunger (plus she has a milk feed at night too anyway)
I assume at 12 months old your DD can find and re-insert her own dummy and find and snuggle to her own comforter?
I think probably pain or poorly. It could be teething. He could also be poorly, or just getting poorly - there are some stomach bugs going round, coughs, colds, that kind of thing.
I know when I feel a big poorly I start wanting a bit more reassurance and cuddles. It could well just be that. This kind of 'regression' (ie sleep going to pot when poorly) lasts for about 5 years, so get used to it. My 6 year old still comes into our bed every now and again for a few days when he's poorly, but not very often anymore. Even my 11 year old came into out bed the other week - that's a rarity at her age though.
So, you know, just one of those things that's part of parenting really.