I am 32 and found out that I had diminished ovarian reserve, meaning my ovaries are acting a lot older than I am. I am almost out of eggs, and pretty much out of good ones. I am probably a few years away from menopause. The doctor can't give me a definite reason for this, but some theories are:
1) Heavy doses or prednisone when I was going through puberty
2) Inflammation from the UC interfered with ovarian functioning
3) Inflammation and trauma from the colectomy/pouch interfered with ovarian functioning
It could be none of these things. Hard to imagine they didn't play some role, though...