A pregnant woman was fired and told that her position was no longer needed. A week later her former position was advertised by her employer. Yes, this actually happens.
A pretextual explanation for terminating an employee is always a sign that something is not right. The obvious suspicion is that the employer terminated the potential client because she was pregnant. The problem with this case was that the employee was barely pregnant and had not yet told anybody at the job. But there was a twist: several months earlier, she had undergone in vitro fertilization. She told her employer both that she was having a medical procedure and that she might not be able to travel starting a month or so after the procedure. From this, the potential client believes that the employer deduced the fact that she was trying to get pregnant and decided to terminate her.
This case is a good example of one of the key differences between pregnancy discrimination and most of the other types of illegal job discriminations - you have to prove that the employer knew that you were pregnant. Many women do not tell their employers right away. This is understandable, to a point, but in that case, they shouldn't tell anybody else at work either. In other words, the rule is tell one, tell all. The boss may hear you're pregnant through the office grapevine, but you may never be able to prove it. My own feeling is that the best policy is tell the employer as soon as you know. This is thoughtful to the employer, who then has the maximum time to make plans for your maternity leave, and it also removes all question of the employer knowing. This sort of communication with your employer should always be in writing.
The case summarized above had an unusual twist, which is that the potential client believed that the employer knew that she was trying to get pregnant, and used that fact against her. There is no question in my mind that this would be, if proved, pregnancy (or gender) discrimination, and therefore, the same rules apply. If you don't want the boss to know that you're trying to get pregnant, don't tell anybody else. As for the procedure and being able to travel, that was something the employee should have kept to herself. The time to tell her employer about limitations on travel was once she learned she was pregnant.