I?d pack a light bag to take and a reserve bag with extras just in case you have to stay longer, your partner can always bring in the second bag for you, just put more of the same from the list below.
But for essentials?
Baby?s don?t need much stuff, they mainly need mummy and boob. If you have problems feeding or don?t want to feed yourself the hospital should have formula and bottles so your little one won?t go hungry. So I would take baby grows x 3 or 4. Scratch mitts x1 pair just in case. Something warm for the trip home. Hospitals generally supply baby blankets and are often very warm, so you only need to worry about vests and things for the trip home. Pack a nice warm going home out fit for them.
Old nightie to give birth in, something to preserve your modesty should you need to nip to the loo during but something that can be thrown in the bin after if need be.
Snacks and bottle of water for labour. Chocolate/snacks for the ward (meals come but 3 times a day, so if you arrive just after meal time and you are starving and the nurses have sent hubby home for sleep you?ll need supplies) Snacks for night time feeds.
Wash bag with shampoo, shower gel cleanser, hairbrush etc, whatever you need to make you feel human and nice again (for some this includes hair dryer and GHD?s. but pack whatever you feel)
Dressing gown, slippers, a few p.j bottoms or nighties and a couple of nursing bras. 1 set of clothes to go home in. 1 or 2 packs of v cheap big pants (instead of paper pants, don?t even bother they are horrible, M&S worked out at £1 per pant so if a few pairs ended up in the bin it didn?t matter) 1 or 2 packs of maternity pads (horrid, but hey ho).
Mobile phone. Magazine (just in case).
That?s about it really. It should all fit in a fairy small bag especially if you take travel size shampoo etc. If I had space I might take ear plugs and an eye mask in case the ward is noisy and a pair of plastic flip flops to wear to the shower (just in case the shower floor is not all that clean)