Interesting, I have an old L4, L5 herniation like you that doesn't bother me much...it's been almost a year since it caused me severe pain, these days it feels more like tightness. I'm only 11 weeks along, so I've been wondering how it's going to hold up during the pregnancy, but the labor issue hadn't occurred to me. If your doc gives you some info on this, will you let me know? I'll try to talk to my OB about it in my next (14 week appointment too.)
i'm pretty sure the goes higher than l4 so you be able to get the epidural just fine. double check with your doc.