Actually, the first large-scale scientific study of women’s body measurements was done well before the 1940s, in Australia:
“In 1926-27, at his instigation, a vast and systematic anthropometrical survey of women’s measurements was made. This was the first of its kind in the world, and as a result, Berlei Limited were able to make garments on a scientific health basis, and this resulted in the invention of the famous Berlei Figure Type Indicator.”
There’s even a movie about it!
Apparently the study was conducted in the 1920’s. Unfortunately, I can’t find reference to a film but did locate a 315 page (pdf) guide to the Berlei archives courtesy of the Powerhouse Museum Archives.
More on Berlei.