Well I did with Lindsay, but didn't know until afterwards when DH said something about it (very considerate LOL). When I had Erin I had a examination and the midwife said I was 6cm and I had a full bowel so she nicely asked if I could empty it. I asked nicely if I could have an enema and she said she didn't want to put me through that. I though how could she put me through trying to go to the toilet with contractions. Anyway as soon as I did empty my bowel, Erin crowned and I nearly had her on the toilet. So it did help immensely.

But concerning your irritable bowel condition you may find you will empty out before labour starts due to nerves.