maxi pads are routinely listed as a good item for a first aid kit. I don't think ER personnel would be surprised one bit to see menstrual supplies used that way at all.

Never forget that the best item to have in your kit is TRAINING.

A roll of quality first aid tape or a cravat ( folded large triangular bandage) is good to have in a kit for wrapping arms/legs. Add in gloves for handling blood.