This is in no way to stand on a soap box about CIO, because prior to last week I was against it for our LO. But after being up 11 times one night, and 4 times the next night over an hour each time with an inconsolable little girl I didn't know what else to do. My mom, MIL, and 2x mom SIL all said we had to just let her CIO. So, we did...
Here's what I found out. If I had not let her CIO, and even done something like pick-up/put-down, I don't think we ever would have known what was wrong. After ditching the sleep sack (she was already arms out, but sleeping like crap anyway), when we let her cry for a few minutes, she ended up flipping to her tummy, fussing for a minute, then out. Like, REALLY out, sleeping 11+ hours. Now, she flips to her tummy immediately on her own (because she hates when we do it for her), sleeps 7p-630a, and she NAPS. At 5.5 months old, she had only napped in her crib twice. I am floored by how letting her CIO helped us realize what was wrong for her to even be crying.
So I know this wouldn't be the case for everyone, but just saying that those who may be struggling with letting them CIO, there may be something they need that, only CIO will help you figure out. Just my two cents
Re: Sleep problems and those wary of CIO