Can anyone give me any advice please.
My girl is day 57 into her pregnancy and has started to become itchy.
I’ve had a good look at her all over and cannot find anything obvious.
I was wondering if it was because her skin is stretching with growing puppies causing the itch.

I’d get her checked by a vet, I’m not sure about dogs but in pregnant woman itching can be a sign of a serious liver condition.

I remember reading a thread on here some time ago about this and it went away when the litter whelped and was related to pregnancy hormones. 

If you go to google and type in 'itching pregnant dog champdogs forum' then you will usually get up all the posts that have ever mentioned itching... (I tend to find that better than using the search box on this site which doesn't always go far enough back or find all the posts).