You can answer this in two ways:
1. When they ask, "When would you be available to start in a position?" Discuss when you plan to return to the work force, and your child care coverage.

2. When they ask, "Is there anything that would prevent you from devoting regularly scheduled hours to this position, and overtime when necessary?" (This is the sly way of getting around the 'we notice you're pregnant' question they really want to ask.) Tell them about the child care coverage you have already set up, and - if this is not your first child - how working regular hours and overtime has never been a problem at previous jobs. If this is your first child, still discuss - briefly - how your child care is flexible enough to handle this.

Oh yeah - and turn a "negative" into a positive. Sneak in something to the effect of "I really want this job - look, I'm here while 7.5 months pregnant and uncomfortable! How's that for perseverence?" lol

Best of luck!

Just be point blank. You will have a valid case if they discriminate against you based simply on your pregnancy. Your pregnancy will obviously take you out of the job pool for a couple months, but if you state that you are the most qualified for the position, and that you will be a company-player when hired... that is, child care already arranged (or ask for child care if you've done your research on the company and know that they offer it), if you do these things (that is, provide solutions rather than simply lay out things that may hinder your performance), you'll have a stronger position to start from than if you try to avoid the issue of being pregnant.

Tell him/her you just won a cheesecake eating contest and your bit bloated.

If you are showing "that big", this will be the first issue addressed, believe me.

What you see if what you get.