My DS is 5 weeks old and since birth (I think) he has flexed and twitched his legs (think like a dog after doing a wee) when I take his legs out of a sleepsuit to change his nappy, take his nappy off or if he is particularly distressed/hungry.
I don't remember my daughter doing this yet I've always thought random jerkiness was normal in newborns but I've made the mistake of googling it and have now convinced myself that there's something underlying going on and these are tremors so wondering if anyone else can share whether their children have done this when newborn?! They do stop if I put my hand on his leg.