Well my IL's live interstate also. Being the in laws it may be different to actually having your own mum there but this is my story..

With my first preg we were living in Nth QLD closer to the IL's in the same telephone call we told them I was pregnant and moving back to NSW to have the baby. This was going to be their first grandchild but I wanted to be near my family for the birth. I wanted my mum to be there holding my hand. Anyway IL's planed to come down when Evan was born and from memory my MIL actually wanted to wait till after I had given birth and settled in but DH said he would like it if they could be here for the birth. So they came down early. They stayed with us in our 2 bedroom flat for almost 3weeks!!
I was a total cow to his parents mostly his mother, but what else can you expect, I was tired, hormonal and completly overwhelmed. I hated having them there, I really think it made a big impact on how long I suffered with the baby blues. I think they really could have caused me to slip into PND if I hadn't already. I hated that I couldn't just sit in the lounge room and flop out my boob, I could if I wanted too but I knew FIL was uncomfortable about it and besides that Evan wouldn't feed properly with some many people about. As a result I ended up with a baby who would only feed properly if I locked my self away in a quiet and dark room. I hated that his mother would do the dishes for us but she is a hopless house keeper and I would always need to redo them anyway. It always looks like she has rinsed the dishes with the old water that has had potatos boiled in it. even when they would go out for the day to give me some time to my self, I would get up to all of their stuff every where and crumbs and food scraps left on the kitchen bench from where she had made lunchs to take with them. I hated that I had to repeat myself over and over that the cat was not allowed outside and to not let him sit by the front door. All the things that bothered me about them being there seem very petty now but at the time it was driving me insane. I was so glad to see the back of them.

When we told them I was pregnant with number 2 I told DH to tell them that they are welcome to come down for the birth but I would rather they didn't stay with us once I was home with the baby. He flipped out and made out as though I had said I didn't want them to have any part of the new baby and that I am always so mean to them. Eventually he could see my point of veiw and told them. They came down about 3 months after teh birth and stayed for a week, it was much easier to handle this time. I had Glenn settled in to a good routine and Evan was a good distraction for them. He helped keep them busy so they didn't bug me so much.

So this is my warning, if you have a really good relationship iwth you mother, and know that you will be able to handle having her around then great, have her there from word go. but if you would like to be able to find your little nook in the new world of mother hood, have her come at least a week or 2 after the birth.

I think my biggest problem was I wasn't able to "nest" with them around, I couldn't even go to the spare room in the middle of the night to get a fresh blanket or clothes when Evan had chucked up on his bedding because they were in there and sleeping against the cupboard with the baby stuff in it.

Why don't you ask your mum what she would like to do, how much would it mean to her to be able to be there at the birth?