There are many women who swear by these not-so-sexy mesh pants after having a baby.
First, they are super stretchy and fit better than regular or maternity underwear 24-72 hours after birth. They are breathable and soft for moms who have had c-sections or an episiotomy. The mesh underwear will allow you to heal without putting any pressure on incisions or your abdomen. You won't need to use them for long but many moms wouldn't have babies without them and I recently read a forum that the moms said that the hospitals weren't even providing them or they only gave them a pair or two.
Consider mesh underwear something you should definitely pack in your hospital bag. You can buy them at health care supply stores or purchase a pre-packed hospital bag like LaborKit which includes mesh underwear in every LaborKit.