The first nursing bras were likely simple adaptations of regular bras, with the addition of a flap or opening in the cup to allow for easy breastfeeding. Check out this catalog listing for a nursing corset!
Momzelle Cotton Nursing Hoodie in Dalhia
What kind of nursing bras should I buy? – Momzelle
A Wardrobe Update from Momzelle Nursing Apparel - TheMonarchMommy
Summer Nursing Apparel from Momzelle
CLEARANCE *New* Momzelle Lace Feeding Bra 2 Colours – Happily Ever
Momzelle Maternity Seamless Nursing Bra - - Assorted Colors
Burgundy Lace Nursing Bra – Delight Boutique
The Best Gift for a New Mom: Momzelle + $50 Momzelle GC GIVEAWAY
Momzelle Breastfeeding Top Review and Giveaway
MomZelle Maternity/Nursing – ResCue Baby Bums
Britt Maternity & Nursing Top in Graphite by Momzelle