I don't think you have anything to worry about. My wife and I just had a baby girl (Eden born on Dec. 29, 2007) and everything is fine. I've been on Azathioprine for a long time, and had been during conception. I was actually wanting to wait until I was off the drugs, but God's will be done.
Diagnosed with UC in 1997.
Medications: 100 mg Azathioprine a day, 20 mg Prednisone a day
Supplements: 2 Omega 3s, b-6, calcium, OrthoBiotic probiotic and multivitamin
No. of colonoscopies: I lost count at 6...LOL!
Last scope: 10/9/05-everything looked ok.