Before my son was born, I packed a bag for the hospital that was stuffed to the brim with everything I had read or heard that I would need. When I came home and got around to unpacking, I realized that I had not used many of the items I brought. So this time around, I am determined to pack less but have it be more useful.
For starters when you are packing your bag (which you should do about three weeks before your due date), you should pack one or two gowns or large t-shirts. While you may be content to lie around in the hospital gown, it can get weird when you have company in your room. Plus you will be much warmer even with a thin gown than the hospital gowns. Second, you should take some slippers or thick socks. My grandmother bought a wonderful pair of fuzzy slippers for me before I had my son, and they were a great gift while I was in the hospital because I could be more comfortable walking around my room and the floor of the family unit.
Also take some things for you to do but be realistic. I thought I would be able to work on projects while I was in the hospital, but a combination of minor problems with my son, lack of good rest, and medication to calm my blood pressure made me unable to concentrate. Instead this time around I will be taking only a few items that can keep my attention briefly. Crossword puzzles, sudoku, and word searches all are great ideas for keeping your mind going while you are in the hospital. Puzzles allow you to focus for just a few minutes at a time, and they are fun to do. You also may want to buy a book to bring or stock up on magazines. (Ask around. Your friends probably have copies of a few magazines you can borrow.)
When it comes to underwear and bras, you can make your own decision here based on your personal comfort level. If you have a c-section, you probably will have a hard time wearing regular underwear. In fact, your doctor may suggest you try to keep the incision site far away from the elastic bands from your underwear. An alternative is to get a size larger than you normally wear. While you may not want to do that to pack, keep it in mind for the future. With all of the tubes and the moving around in the hospital bed, you probably will not be wearing a bra during your stay but bring one if you are more modest and think you will want to wear one on your ride home.
Bringing one change of clothes to wear home from the hospital also is a great idea but one that takes careful consideration. Basically you will want to wear something comfortable home, but you probably want to look decent, too. For most women, their uterus does not shrink back to its normal size (or some approximation thereof) until about three days after birth. That means that you may still look and feel very pregnant when you leave the hospital, which is why picking out clothes can be tricky. Your best bet is to get pants or a skirt with loose elastic in the waist or one of your smaller pair of maternity clothes. That way you can look nice either way. For a shirt, pick something that will hang pretty loosely on you because you probably will not want to have anything tight.
When it comes to toiletries, I believe in bringing smaller versions of the items you use at home. Stock up on a cute bag and put travel-size versions of hair spray, toothpaste, and even deodorant. That way you can get to the items easily and can use them more easily while you are stuck in the hospital. If you will worry about your hair, bring a large-toothed comb (it is likely to get knots during labor), a spray bottle for water, and clips if your hair is long enough. These items should be enough to make your hospital stay pleasant and manageable.