Update 3/1/2016 Reagan National has a dedicated nursing mothers room in Terminal A. Moms can express breast milk by pumping or breastfeed here if they want more privacy. There are 3 comfortable nursing rooms in all throughout the airport. Room amenities include rocking chairs, electrical outlets, and baby changing tables.
Terminal A: one room located just prior to the TSA Security Checkpoint
Terminal B/C: two rooms located next to Touch of Color on National Hall
Traveling Mom Valerie at Reagan wrote: "There is now a lactation room in Terminal A (mostly Southwest Flights) just before security (not airside). This doesn't help for people flying on the other airlines, since Terminal A is a schlep from the other Terminal and it wouldn't be realistic to use it unless you are on a flight out of Terminal A."
Some moms call it Nursing Room, Breastfeeding Room, Lactation Station, and others Lactation Room. MomsPumpHere Nursing Room Locator (also Airport Lactation Rooms Locator) is a breastfeeding room finder, nursing room finder, lactation station locator, and lactation room finder. We find moms nice, quiet places to breastfeed or breastpump no matter what they call it. Lactation rooms also help moms relieve oversupply of breast milk which can cause mastitis while breastfeeding.