Medisave for pre delivery medical expenses

Does anyone know how this works? I want to use Medisave for my pre-delivery medical expenses but the nurse asks me to settle the bills each time I ask after my appointment. Does it mean that I pay first and get reimbursement later after delivery? Some posts share that I will need to bring all the receipts. How is the money ($900) reimbursed? Via check or bank account? I don’t seem to find any information online.#advicepls #firstbaby