I did a chunk of renovation work when pregnant with my last. I found the acid reflux being bent over too much made me stop, but until then: Good respiratory mask If your house is old, check for lead in the paint you're sanding / removing and keep yourself away from any dust if it's present No ladders! Check for low or no VOC paints Check for lead in your water supply (again if your house is old), you can get filters if it's present. Exciting times though, it's so much better to get it done pre-baby!!
Its ok as long as you aren't bumping your tum too much and wearing a really good respiratory mask to stop the dust particles.