We used a ****roach bomb in our house. It was also one of the ones we got at the supermarket. It worked well for about 2 weeks, but then eveything came back...
Anyway, we did it in November, and I think I would have been around 20 weeks. DH made me do it, even though I told him it could be bad for me, but he kept saying its bad for him too (asthma). I did it because he wouldnt, and I didnt do it, it wouldnt have gotten done! I have no idea if its bad or not though, but I would wait until 2nd or 3rd trimester to do it.