When to increase A time: This just takes watching LOs sleepy signs and also nap quality. I found my son was usually ready to increase by 15 minutes about every 4 weeks. So, their age is kind of a good measure too. If it's been about a month since you last changed A time, then it may very well be time again. But honestly what I usually went by was short naps. When he went down to 30 minute naps, I knew he was UT and I needed to increase A time by 15 minutes. Worked like a charm! since you're starting wind down before you even *see* sleepy signs, it sounds like short napping may be a sign for you too. Babies at 11 weeks typically do about 1h20-1h30 in A time. If that's what you've got right now, once wind down etc. is done, then you're fine. It's possible your short naps are due to being undertired, so you might increase until you get to the 1h20-1h30 mark and see if that helps.
The other possible reason for the short naps you're getting is that you may be hitting the sleep change that happens around 12 weeks of age. Their REM/non-REM sleep changes, and they start to come intoa light sleep phase at 30-45 minutes. This is new to them (they used to be in a deep sleep from the word go!) and so they tend to wake up!
We need to teach them that they need to fall back to sleep after the light sleep phase. One of the best methods for this is the 'holding-thru-the jolts' method. I've reprinted an excerpt from the FAQ section to help you:
Going in at the 35 min mark and waiting for the jolt. The beginning of the rise from deep sleep happens at about the 38 minute mark, so if you are there at the 35 you will catch it. Prepare to spend 20-45 mins in the room the first few times you do this. I started it today and it is already working. Get comfy, perhaps on a stool or standing by the crib and gently place your hands on your babys upper arms while she is swaddled. You are basically providing some pressure so that when/if she jolts, your pressure will prevent a startle awakening. If baby opens her eyes, use one hand to hold her arms and the other to shield her eyes with your hand. If the room is really dark you may be able to avoid the eye-part. Otherwise, maintain this position until baby falls back into deep sleep again. You will notice her breathing quicken when she comes out of sleep and she may grunt, life her legs and roll her head side to side. If you use a paci, you can insert it, but don't do so before she opens her mouth for it. Shoving a paci in there when not requested can actually wake her up more. Follow her cues for paci or out. You may put it in and she will close her eyes, rest and spit it out (keep holding her arms) and then suddenly seem like she needs it again - put it back and continue being careful not to let her come out of sleep due to jolts or wanting that paci - it can feel like a juggling act
The first time it may take her 20-30 mins to fall back into a deep sleep, but if you continue this for all naps, you will see that the time it takes her to fall back shortens and this means you will spend less and less time at the cribside.
It is often easier to just sit thru 1 nap so you can see exactly when the jolting happens for your child. Then you can make sure for all subsequent naps that you are there BEFORE that jolting begins. If you don't get there until aFTER the jolting begins the method isn't as effective. In my experience it usually takes about 3 days for this to work, but you have to be very consistent about being there before the jolts begin for each and every nap.
The first time you try this method your LO will probably still wake up. That's OK! just keep going. And, you might also be surprised that if you KEEP doing the holding down after they open their eyes and seem awake that they can still fall back to sleep! So don't let up on the pressure until your LO is for sure crying and wanting to get up. Hopefully by the end of the first day your LO will start going back to sleep. By the 3rd day LO may be falling back to sleep on their own without your intervention.
