This happened to me unfortunately. I was a good employee and worked there for 4 years, had letters of recommendation and won employees of the month. I told them I was pregnant when I was 5 months pregnant and by the time I was 6 months pregnant they had hired another girl to take my job. I was "laid off" due to "lack of work". But I know it was because I was pregnant.
If you're in the U.S and not in a right to work state they can fire you without a reason (I'm in one of those states and in the handbooks it states that the employer (I'm an employerish type person) can fire you under any circumstance they want without reason and without notice. I've seen it happen.
Can they fire you for being pregnant? No. There are laws against that. Can they find other reasons to fire you? Yes. I've seen that happen as well. It happened to my friend. She was 6 months pregnant, no longer had her thin body and was a bartender. She had one complaint come in...her first in 6 years...and they fired her on the spot.
Btw I should add I am from the UK, so things might be different, but you shouldn't get fired for being pregnant, I know maternity pay is different, like you're entitled to it only if you got pregnant whilst you were working for the company! How weird!? But I actually got my job because I was pregnant, I was on a qualification course and well at the end they find you a job, as they couldn't send me anywhere they kept me gave me a 9 - 5 job and another qualification :)! but I am from the UK and things I guess are different!! :) x
Well there's a lot of factors that would come into play. If you do something wrong, they can fire you pregnant or not. If your state isn't a right to work state they don't need a reason to let you go. However, they cannot fire you because you're pregnant. Many companies do it anyways, just under a different reason to avoid being in trouble.
You can get fired for breaking a rule, but you shouldn't get fired for being pregnant, its against the discrimination law! :) and if they fire you for being pregnant you'll be able to take legal action! x