I think like Farmgirl said that the concern is more form mum than bub at this stage, early in pregnancy it can be a problem, but at this stage I think it's more about the relaxin in your joints. Think about it this way though... If you have another young child, you'd be picking him/her up so your body has to be able to deal with an amount of weight. My son was weighed on Wednesday at 15kg and I still pick him up most days, it's never for long, mostly to put him in his car seat etc and my Dr has no issues with me doing it.