Should i tell HR im pregnant?

Dani
I've already told my bosses and most of my colleagues but I'm wondering if I should officially report it to HR. We are going through a huge organizational restructuring at my company and my company is notoriously not so fair to its employees so I am a little concerned that I could be treated differently or this could give them an excuse to let me go but (may be being paranoid) but I'm thinking if it is in writing with HR that will be harder for them to do. Those of you who have been through this before what do you think?