thorny situation no matter what

but there's hardly anything can be done to help yourself legally.

employers are smart enough to not fire you or take back the offer right after you tell them about your pregnancy. but if they really want to let you go, it is pretty easy for them to find some other ways to do so, say start by making your days uncomfortable, either give you too much work, or not giving you any interesting work at all.

the outcome in a large part depends on your ability to work with your direct manager.

good luck.