Congratulations on your preganancy and hearing your babies heart beat.
I have Ulcerative Colitis(IBD) and IBS both. I am also 30 weeks pregnant with my second. During my first pregnancy I had neither of these conditions,and I must say my pregnancy was probaly easier for it. I cant say exactly how you will be able to deal with the stress of IBS and pregnancy,because I also have IBD and that is very different than IBS. But,I can say that the bowel spasms(cramping) are pretty normal and that hurt soooo bad. There have been times I cant even walk because because the spasms are so intense. I told my OB about these pains and how worried I was for the baby. She said as long as the cramping doesnt change,like that it feels the same as it always had then everything should be fine with baby. It's still really scary because you dont like to feel any funny pain in your tummy while your pregnant,but just remember these pains are most likely from your IBS(if they are pains that you are used to and have had before your pregnancy). My IBD is currently in remission,but I still struggle with various pains throughout everyday. I'm mostly concerned about delivery and what that will bring for me...hope I dont flare up. Anyway,sorry I couldnt be better help,just know your not alone