Where are you all located?
In Ontario, we have a program called
Motherisk, run out of Sick Kids' Hospital in Toronto. You can call the helpline and get a personalized risk assessment -- skilled researchers comb the medical literature (they have standing files on a lot of things) and let you know what the potential risks are for your situation. It may be worth a call. (There are both 1-877 and local numbers).
A few years ago, I attended a seminar run by a local Crohn's and Colitis group that featured a number of OB/Gyns talking about Crohn's. The general consensus was that the drugs I was on were low risk during pregnancy -- I believe there was a slightly higher than normal risk of a baby being born with a cleft palate from the prednisone, but that's not a huge problem -- I know a number of great people who were also born with this issue. As to Remicade, they were saying not to discontinue it during pregnancy, and that it was not a problem for a healthy birth. But nobody could answer my questions about whether any problems were likelier to develop *after* birth with kids whose moms were on Remicade. There were no longitudinal studies at the time. Maybe there are some now. It's something you can ask if you call Motherisk.
(In the meantime, I haven't been looking into this at all).