I took loads that I didn't need for DC1 (EMCS) so went back to basics for DC2 (ELCS), we had a 4 day/3 night stay.
For me:
Camera, phone, charger.
3x pj bottoms, 3x vest tops, 2x nursing bras, 2x leggings, 2x tshirts, 1x cardigan, 10x big pants, 4x socks, comfy trainers.
Brush, baby wipes (for me), 24x night pads, 10x breast pads (pairs), sensitive shower gel, 1x baby sponge, toothbrush, toothpaste.
Pregnancy/feeding pillow, water bottle, cereal bars, boiled sweets.
For DC:
6x babygrows with built in mitts, 6 vests, 1x cardigan, 1x hat.
Travel change mat, 28x newborn nappies, cotton wool pads, small bowl (to dip pads in lukewarm water), 6x muslin, 1x blanket.
1x car seat.
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DC1 was formula fed but hospital provided for us then, if not I would've taken a box of those small premade bottles in.