At what point do I worry about baby not laughing?

[Titsalinabumsquash]

I've had 3 babies that have been 'early' meeting milestones and now I have a fourth that isn't.
Don't get me wrong I think she's perfect but she's 20 weeks old and although we get loads of smiles and grins and a lot of chatter, she doesn't laugh.
She was 4 weeks early so I'm not sure if that makes a difference, one of my others was 4.5 weeks early and was still ahead of the curve with his development.

I'm not sure when I should be concerned, I'm not atm but all the babies her age around me seem to be rolling, laughing, sitting etc and she's still quite content laying on her back kicking and chatting and cooing.

Mine didn't laugh at that age either and when she did start laughing it was only an occasional little chuckle. She still isn't a big laugher as a toddler but very smiley and happy. If you still see your HV then mention it and see what they think but I wouldn't worry that a baby who is smiling, engaging and happy isn't laughing yet.

Maybe she's just a happy, laid back baby?

DS1 laughed, a proper belly laugh at 5 weeks (I found the film of it this week) but he was usually completely miserable and has generally been a miserable, anxious, difficult child.

So I think early laughing is probably over rated.

DD didn't laugh until 5 months & then almost only at her big brother. I never worried about it.