This is a lovely women's maternity dress by Old Navy. 
Please note: there is some stretch to the measurements below.
When laying flat, armpit to armpit measures 21 inches.  
Shoulder seam to the bottom of the arm cuff measures 24.5 inches. 
When laying flat, shoulder seam to the bottom of the dress measures 39.5 inches. 
The measurement from the back/neck collar seam to the bottom of the dress is 41.5 inches. 
This dress is in great condition and comes from a smoke-free home. Thanks for looking!