I havent started jabbing yet but I bit the bullett and told my boss I was starting IVF... I'm a terrible liar and didnt want to have to try and make up excuses for when I have to go for the blood tests/scans every second day during FSH. He was super good about it, very supportive and said I can take sick leave for any of my treatments. I didnt tell my immediate team so I'm sure they'll be wondering come that time but it's such a relief for me that it's out in the open with my boss, I'm glad I told him.
Think it totally depends on your workplace and your boss though and how supportive you think they'll be.