My employer when I was pregnant was a massive compnay, and they wanted me to provide a "fit to work" letter from my doctor/midwife if I wanted to work after 34 weeks. I ended up just going to my GP and asking for it. He just asked me when I wanted to work until and he put some really vague date like "end of february", lol. My work accepted it and all was good. I'd just get the letter to keep them happy. You dont want them making your life diffcult right now. As long as your healthy you wont have a problem getting a letter to say so. Maybe check with your HR department or Industrial Relations in your state if it seems a bit dodgy.