Boobs?

Tiffany • Christian. Mother of 3. 3 living and 1 angel. 10 years together married 7.
How often do boobs change size, shape and size of Areola? If it a pretty good indicator of pregnancy if it changes?
I decided to put it to the test this month just in case I did concieve. 
So far my boobs are slightly bigger, my shape has become bigger and color is darker. AF is due the 24th