crossfire while pregnant

Any mommas still working out while pregnant? I've been doing crossfit for almost a year.  I plan on sticking with it as long as possible.. but just curious as to when I need to worry about modifications and safety. Do I have to tell my coaches right away that I'm pregnant?  We have a very small box and I just don't want word to get out to the whole place just yet. I'd rather wait to tell anyone!