My son would sleep 10 to 12 hrs every night from the time he was about 3 months old. All the sudden he's waking almost every hour. It's worse than when he was an infant. Also would like to know if night feedings to get him back to sleep will cause weight gain as he is in top percentile for weight and height.
First of all, lots of babies change their sleep habits at about 4 months. It's sometimes called a sleep "regression" but it's more a permanent chance in how the baby's brain is wired. So you can't expect sleep habits at 3 months to carry on past that.
A 9 month old is capable of eating enough during the day to not need to feed at night, so first order of business is to taper off the night feedings.
Once that's out of the way, your kid needs to learn how to soothe themselves back to sleep. And then need you to give them the opportunity to learn that.
As your child grows, it will also get more energy and sleep requirement may become a bit less. It's then important to make sure the child gets enough play time that is physically challenging enough for the child. If the child lacks the necessary exercise time appropriate for him, then the child may not sleep well during the night.
We have two sons, 4 and 1.5, and they both went through a similar pattern at some point. We were excited when at 3, 4, 5 months old we had "good sleepers" compared to some of our friends' kids, but then each went through (multiple) different periods of regression at some point. Now they both generally sleep 11-12 hours every night, but you never know when you're going to have "one of those weeks".
My advice is:
- Try to take the long view. Meaning that things will probably change, and change again in the near future, so don't worry too much about what's causing the behavior today, or this week. Instead, try to work towards setting good nighttime patterns that will pay off in the future. Whenever we "intervened" in our boys' nighttimes, we always kept lights as dark as possible, used very quiet voices, kept them in their own rooms/beds, etc.
- Experiment with different levels of intervention. In other words, when your son cries, don't necessarily go immediately to him and pick him up. Try shushing from outside his door, or humming a little tune, or just patting/rubbing his belly. Whatever intervention you make will be what he learns to expect, so the more you have to do to get him back down the more he'll get used to that. In my experience, it's much nicer to just have to give a few pats for a minute than it is to have to pick up/rock/walk around. (We actually had a period of time where we could shush one of our boys from our bedroom down the hall without even getting out of our bed. At that point, I think he just needed to know we were out there somewhere, and a quick shush was enough verification for him.) You never know what's going to work, so try some stuff out, and maybe you'll hit on his This-Is-The-Thing-I-Need-As-A-9-Month-Old-At-Night. But of course, it will likely change again soon!
- Try to eliminate the nighttime feedings, but don't beat yourself up if you give in now and then. Your high-percentile 9-month-old probably doesn't need to eat during the night, but may instead use feeding as a way to feel comforted. Try to find a different way to give that same comfort. At the same time, you're probably a very tired person now, so don't get down on yourself if you occasionally go "Nothing's working, screw it, I'm feeding him."
There are so many things that could cause this regression that I wouldn't worry about getting to the bottom of it. Instead know that there's a light at the end of the tunnel and he'll start sleeping again soon if you work on it together. But of course also remember: there will be another tunnel after that! Get as much sleep as you can now. Good luck!