The Maryland Zoo said it would work on becoming a nursing mother friendly place, but still is not as of 2015.
In 2013 Mom G. Rubino wrote a bad review for their lack of a nursing space and unpleasantry overall and they responded below:
Note: As of June 2015 there still is nor dedicated nursing mothers area, except for maybe the First Aid station.
Kate H, Public Relations Manager at National Aquarium stated:
"We do offer a private guest area for private needs such as breastfeeding. Can I ask if you asked any of our staff for this option? I want to make sure our staff knows where to direct guests with these needs. Also, I'd love to hear from you where it would have been helpful to see signage for this room. I would like to bring those suggestions to our team."