I was told 36 weeks I should send my form in.
My hospital doesn't let you until you are 30 weeks pregnant :]
I had to between 24-28 weeks. Now if anything happens i just walk in, give my name and go straight to L&D. My forms are already signed and my insurance approved. You dont want to queue and fill in forms while in labour, so if your hospital offers that service, do it. Plus we received a free 4D scan if it was completed before 28weeks.
I was at my hospital for another ultrasound the other day and asked if I could preregister and they said they don't do it so I don't know if all do. I delivered at a different hospital last time and they did let me.
It's a good idea to do it now. Other then getting your medical records and insurance info. It's also about getting what you want in order like who you want and don't want there with you. Do you want your baby daddy to cut the cord. Do you want an epidural or pain meds. There is a whole lots of questions they will ask and better to get your wants and needs across before your in actual labor.
I already have. My hospital and Dr's office likes you to do it around the beginning of your 3rd trimester. It is better to have it done before you go into labor, so they have all of your insurance info, personal info, and any medical records they may need from your Dr's office.