If you need the placenta to bring to hospital because you are going there after the birth to register, then just put it a plastic container and bring it along. If you have a private midwife that arrived soon after you birth, then you don't need to go to hospital to deliver, as she will do all the paperwork you need for misrad hapnim. However, if she doesn't know you beforehand, and it was an intended unassisted birth, then no midwife will come to write you paperwork. Only if the intended homebirth was too fast and the midwife didn't make it in time.