How do I handle this work/pregnancy situation?

First of all, you should take a PAID maternity leave. But if you really aren't, or they don't allow that for some BS reason, then you are not obligated to tell them (i don't think). Because I got a lot of discrimination at my last job while I was pregnant, and there where two different kind of people, the people who didnt think I could do the work and looked down on me for it, and the people that didnt think i could do my work and were too helpful. I don't quite know what to tell you in your situation, but Id not say anything and if anyone asks tell them, but really see if you can get a pain maternity leave. Good luck either way, I hope you have a happy healthy baby, and a easy delivery (if there is such a thing) Good luck!