First you will need a bag, will it be one that mom can use later, or one that mom can use to put all those baby items in after the baby is born.
Make sure the bag is big enough for all the items you want to put inside of it.
Here is a list of items mom could use on her hospital stay, and things she will need:
insurance card, some cash
phone numbers of those she will want to call about the baby
a calling card (some hospitals restrict cell phone use)
hairbrush, hair ties, a little makeup (you'll want at least one nice picture with the baby)
a camera
toothbrush, toothpaste, shampoo, antiperspirant, socks (some hospitals do supply these, so you can always call them to see what is supplied)
a pretty presentable robe and slippers
about 6 pairs of cheap underwear (that she can toss out after wearing them)
a comfy outfit to go home in (her pre baby clothes won't fit yet)
a book or magazine
a journal to start writing down those wonderful thoughts and ideas and dreams for the new baby to be shared later in their life. This is also great for the guests who come to see the baby and new mom to write in their wishes.
*****
Things you will not need to pack since the hospital will supply:
Nightgown/pajamas
maxi pads
diapers
receiving blankets
any projects like birth announcements since there probably won't be time for that
*****
a camcorder maybe a nice gift too for the new parents (and a great gift idea for the grandparents too)