Help - short naps!!

[Dmum]

My DS (9 months) had a lot of sleeping problems when he was younger and, after sleep training and cranial osteopathy, settled into a fairly regular routine. (3 naps a day, sleeping through the night, etc.) He can settle himself to sleep (no dummy,etc); his room is dark; he's in a grobag; etc. He sleeps 12-12.5 hours at night. About 6 weeks ago, he started protesting about his 3rd nap and I realised he was probably transitioning to 2 naps. This went quite well and he seemed to settle into a routine of having just over an hour for both naps, sometimes a bit longer. Night sleep was unaffected. The problem is, for the last week and a half, he'll only nap for 35 minutes at a time. Occassionally, he'll sleep longer, but there's no pattern to it. He wakes up from naps, clearly still tired, and spends a lot of his day fussing and grumpy. I've tried leaving him to see if he'll go back to sleep, but once he's awake, that's it. I've tried keeping him up longer, putting him down sooner, giving him calpol in case it's his teeth. It's driving me crazy!! Is it an age thing - to do with mobility (he's just started trying to pull himself up to stand)? He also seems very frustrated that he's not getting about like to wants to. Anyone else been through anything similar? Please help!!

Maybe if you try to encourage him to have just one nap, that will be longer and more refreshing?

Thanks for your suggestion, Oakmaiden. DS can only stay up for around 3.5 hours before he gets really, really overtired!! He needs a nap mid-morning and mid-afternoon. He gets up around 7am. Goes for a nap around 10-10.30am. Again around 2.30pm and then bed at 6.45ish. I've already tried keeping him up as long as he could manage and he still only slept 35 minutes.

Dd did this, but I'm having a problem remembering when it was!

I think it was around 12 months, but it seemed to be that she was almost ready to drop the morning nap, but not quite. It lasted about 2 months, then we dropped the morning nap. I do seem to remember that the days where she only slept 15mins in the morning worked out better in the afternoon though so perhaps you could try cutting the morning nap in the hope that he'll have a longer afternoon one?

Much sympathy though - we're going through it again with her getting up time now (I think nursery wears her out too much which has a knock-on ffect on her sleep).

It must be that he's slipping into that lighter sleep period and waking fully instead of slipping back off again. My dd does it around 45 mins after nodding off, I hear her start to shuffle and snuffle and occasionally whimper, like clockwork at that moment. But she mostly settles back again. If something's bothering her, whether an external noise or a discomfort (heat, cold, teeth) she'll completely wake up at that point whereas if she doesn't she'll sleep another half hour or so and wake really rested. Is there anything you think may be rousing your ds when he hits a period of light sleep?