#2. Dawn Marie
Dawn Marie was part of WWE at a time when women were used as eye candy and would be put into some shocking and controversial storylines. Dawn was put into a lesbian angle with Torrie Wilson at one point that led to Dawn marrying Torrie's father and then him dying on their wedding night.
It was an odd angle, but it was the way that WWE once was. That being said, Dawn Marie wasn't as athletically gifted as the female wrestlers in the company at present. Marie was signed based on her storytelling ability rather than her in-ring ability. Her time in ECW certainly helped along those lines, too.
Marie announced that she was pregnant back in 2005 and WhatCulture confirmed that she was almost immediately released from WWE with the official reason being given as "creative had no ideas for you." Marie obviously felt that she had been fired for reasons beyond her control and went on to sue WWE and filed a complaint in the Equal Employment Opportunity Commission.
Of course, this was a PR situation that WWE wanted to avoid in future and has since supported many other women through their pregnancies.