Good sleeper gone awry! Please help!

[bleedingheart]

I realise that many of you have far more sleep issues with DCs than this but any advice or experience would be most welcome.
DS is 3.4 yrs old, he has been a reasonably good sleeper from day one. He's rarely had big naps but as he slept through from 12 weeks, I could cope with that.
Just lately we are having real problems settling him for bed. We haven't changed the routine in two years(bath/drink/books/teeth/toilet/bed/another story...) except the addition of the toilet trip following potty training.
We've normally left him settled after a story in bed and he'd fall asleep within 10 mins, no fuss. (Lucky I know!). Just lately he has started screaming the place down and complaining about it being too light/not light enough, needing the toilet, not being tired (he's very active all day and knackered by this time!), wanting another story, wanting to brush his teeth etc.
I've tried to discuss it with him at the time but he just cries. Discussing it with him in the morning he says 'I was naughty mummy!' which is not really how I want him to think/feel. DH didn't get him settled until 10pm last night. I am pregnant with DC No2 -could this be having an impact?
End of ramble -help please!

I think he could be possibly reacting to the change he feels he is going to have to adapt to. My DS is 3.5 and he recently had a little sister from my Ex H and he started not wanting to go to bed, in the end after coming down a few times in one night we decided to be firm with him and hold the door shut on his room until he got the idea that it was bed time and he should be in his bed. I know some people might not agree with this course of action but it works for us and I don't think it's being cruel, when he calms down and I can tell he's got back into bed I go and give him a cuddle and kiss him goodnight tell him I love him and I'll see him in the morning, and then he stays there for the whole night.

Also have you sat him down and talked about the baby and got him involved in the decisions, ie names, decorating bedroom, choosing items for the baby. me and Ex H did this with DD who is 7 when we had DS 3.5 and she had her moments but she seemed to adapt better than some of our friends older children when they had had siblings, this may also help him to see that he will still have attention paid to him and he might naturally stop being a pain at bed time.

Thanks turtle16. We have discussed the baby with him and we have involved him as much as we can. He's very excited about it (although I realise that there will naturally be unease and jealousy). In fact, yesterday he said, 'I shouldn't be noisy at night because I will wake the baby in your tummy.' I did reassure him about this but...

Thanks for your advice. I'm very worried about the effect of DC No2 on him. I guess we're going to have to keep being firm and reassuring him.