Marisa (6.5 months) has been doing this for some time too. I swear she has an alarm clock hidden in there! She will whimper/cry in her sleep for about 10 seconds around 3 or 3:30 every morning (but not wake) and then wakes at 5:20 am - and I mean this doesn't vary by a few minutes. Lately, luckily she has been whimpering off and on for about 10-15 minutes and then going back to sleep for 30-45 minutes or more. Unfortunately, I usually can't go back to sleep myself! But why the same time every morning? I'm scared to try WTS because I don't want to disturb her even more and make her unable to go back to sleep (which used to be the case). I've tried later bedtimes, earlier bedtimes, longer naps, shorter naps (DD naps approx 3-3.5 hours a day with two longer naps and one catnap). When she does wake early I try not to let her nap before 8:30. Anything else I should be doing or just keep rolling with it and hope it eventually shifts later?