I ended up taking a female cat in 6 weeks ago & it wasn't until 2 weeks ago I noticed she were pregnant as she is long haired so hid it well 
I have an idea of what to do etc as had a pregnant cat a while ago .
She has taken root in a chair thank god its leather & won't move for food or anything , Oh and my 4 cats are on guard which is a bit odd
I got her a small DG cage and made it in to a safe space for her iyswim , though she hasn't been near it .
So is their a way I could possibly be sure that she is in labour without been invasive etc ?
Or should I just leave her be and check on her in a bit ?