Its a tough one Nae and it is something that I haven't been through but I am wondering if you could just keep talking and not really give them the opportunity to ask follow up questions.

I am thinking something along the lines of "no, this isn't my first, I had a little girl previously, but we are so looking forward to meeting this one, we [find out the sex/paint the nursery/ whatever] next week and then we have the pressure of trying to find the perfect name, choosing names is just so hard, there are no many things to consider aren't there. Now, how long did you say you were staying for?"