Absolutely on the frozen water.
Can I also add huge knickers? I'm talking about full-on apple catching, belly button hugging, acres of cotton, granny knickers. There's logic in my madness I promise you and it's highly unlikely George Clooney or other yummy doctor will be checking out your knicks so don't worry. Firstly (and without going into unnecessary detail), despite your best efforts and frequent pad changing, your underwear for the first couple of days is going to get messy so you don't want to be wearing anything fancy or special. Secondly, you need to hold a maternity pad in place even with the sticky bit and wings. Thirdly, you're going to be tender and don't want elastic rubbing on any sore bits, granny pants elastic is low on the legs and high on the waist. You can get paper knickers but they're vile and if you pull too hard then they rip. I got a five pack of granny knickers from Asda smartprice for £3 or £4 and threw them away afterwards.
Also, lipbalm. It's very dry on the wards and your lips won't just chap, they're shrivel up into stinging little strips of leather. An essential if ever I saw one.
You might not want food in labour but stick a snack or two in your bag for on the ward, I wasn't hungry in labour but around three or four hours afterwards I was ravenous and had just missed the dinner trolley.
Don't forget your birth partner! Get him/her to pack themselves a small bag too with some snacks, a drink, basic toiletries (toothbrush/paste and deorderant), and a change of t-shirt/top so they can freshen up afterwards, bearing in mind that they crank up the heat in the delivery room right before the actual birth so it can be sweaty and they might have been up all day/night too.
Don't forget your maternity pads. The ones the hospital provide are vile and about as absorbant as a housebrick. I liked the Mothercare ones, they have wings.
Take a book or magazine too for on the ward. It's a bit boring when all the visitors have gone home, those little TVs aren't much good (nothing on anyway), and I found I was too keyed up to sleep much so a book helped pass the time (that and gazing lovingly at my newborn of course).
I found that these were not needed:
- thick socks, the wards are hotter than hell so you won't need them to keep your feet warm
- going home outfit, I just got DH to bring it in with him on the day
- baby wipes, the hospital give cotton wool and warm water which is fine for the first few days