I think it depends on the surgeon girls,they all have their own methods and post op instructions based on their surgery,I had overs,and had to wear a bra immediately,I have known people with unders just wear a breast band and no bra,some have had to wear both,in any case I think the post op dressings are tailored to the individual,by each surgeon.You will need a post op bra eventually,so I would get one or two anyway.xxx