This is a lovely women's maternity dress by Old Navy. 

When laying flat, armpit to armpit measures 17.5 inches.  
When flat, the waist area measures 17 inches. 
Shoulder seam to the bottom of the arm cuff measures 18.5 inches. 
When laying flat, shoulder seam to the bottom of the dress measures 29.5 inches. 

This dress is in great condition and comes from a smoke-free home. Thanks for looking!