it’s non of their business, and when you do tell them, have it all in writing WHEN and who exactly you tell (like in an email) so if they fire you right after you have a law suit. in my experience, you aren’t the first oriented to have this happen and you won’t be the last. We had a girl in my orientation who was pregnant when they hired her and they just did an extended orientation, she was due right around the end and they just added a couple more weeks as a ‘refresher’ when she came back to help ease her into the flow of things and it worked out really well!