Minou, congrats on your upcoming birth!
If you feel comfortable doing this, I might suggest you visit with another OB/Gyn for a 2nd opinion. High-risk OB/Gyns are culturally attuned to a patient who needs a lot of interventions. If your pregnancy has been normal and your baby is presenting normally (not breach, not "sunny-side up") then it seems reasonable that you should expect a vaginal birth. Maybe getting a 2nd opinion from a regular OB/Gyn will give you a different perspective. I did not use a high-risk OB for either of my pregnancies, even though I knew I had IBD during the 2nd one. But i have not had abscesses or other complications of Crohn's like you describe.
Is this your first child? Has the OB examined your perineum to see how the scarring looks?
Are you planning to have a doula present during the birth? There are ways to push a baby out that will minimize the chance of tearing. What kinds of preparation or training have you done for the birth? In normal tissue, a tear heals much faster than an episiotomy - you should have a conversation with your OB/Gyn about that, too.
In the birth of my first child, my OB/Gyn cut my perineum after I'd been pushing for a while. In my 2nd birth, he didn't and I tore, but both times I healed just fine.
I should mention that I fired the OB/Gyn who cared for me during my first pregnancy at 34 weeks because he could not accomodate my birth plan. He was not a high-risk OB and had a 60% c-section rate. I went to another OB for the remainder of my pregnancy and had a perfectly normal vaginal delivery. You can change OBs even this late in the game if you want to. Really.
49 yrs old, IBD diagnosis in spring '01. Proctitis, gastritis, ileitis.
Currently taking Pentasa (3g/day), Sulfazine (1.5 g/day), Prevacid, folic acid, vit. D (2K iu), flax seed oil (2 tsp/day), mesalamine enema as needed. Gluten free as of 5/30/11.