My 9 Mnth Old

I have an 8.5 month old. He slept through the night from about 4 months - 6.5 months like a champ and then started waking up every 3-4 hours. My ped said separation anxiety is common at this age. I just pull him into bed, nurse him, and he's asleep within 5 minutes. Then I put him back to bed. It's exhausting, but I figure he just wakes up alone and needs his mommy. :-)

It's common for babies to have sleep disruption as they hit certain milestones, some of which has already been posted.

Dr. Sears has some excellent expert advice on sleep issues:
http://www.askdrsears.com/topics/sleep-problems

Could it be too hot for her?

Is she teething?
any changes in her schedule?
any stress in your life?
any chance she has an ear infection?
sinus infection?
cold?

children go through lots and lots of changes- it can be hard. but, I find when I am observant and cue into clues my girls give me, I can usually fix the problems in no time.

Best wishes-

You need to google "sleep regression." The website askmoxie.com has a lot of great advice about sleeping, especially about a 8-9 month old baby.

Does she have a night light? Any changes? Does she have teeth coming in?
Rock her, rub her back, play soft classical music, or lay with her. I know it is a change, but you have to roll with it. Sounds like she was a really good sleeper, now that she isn't it is hard to adjust. She is sleeping properly, just not the way she used to. There is always a reason though. Kids go through so many changes and some are not for our best lol

It is very normal for them to have sleeping issues around this age. You could read the no-cry sleep solution and do that method.