Hellobee Boards

I haven't had the need for a nursing bra yet, but I do know that Nordstroms will convert any bra into a nursing bra for a nominal fee.

Nordstrom will alter, as PPs have mentioned, but beware of underwire. Some Nordstroms (especially a really good one, like at the Natick Mall) have nursing bras.

You may want to google your area to see if there is a BFing center or baby store with a good bra selection (I imagine there would be somewhere higher-end like the Back Bay...).

I HIGHLY recommend the Bravado bras - either the Body Silk Seamless (less support, but super comfy) or the Bliss (structured, great for work). You can buy them both on Amazon, and the sizes run very true in my experience. They are $$$, but well worth it, and very comparable to what you will find at Nordstrom.

I bought one at soma, and it's awesome. I may go down a cup size though, I was slightly engorged when I got fitted.