Telling Your Employees At Work

I started a new job when I was about 10 weeks pregnant. My boss and HR department knew during the interview process because I informed them of my intention to take maternity leave in early 2016, (even though I legally didnt have to tell them.) They hired me anyway. No one else at work knows. I am starting to struggle wardrobe wise and it might start to get obvious. I am an Executive and am a boss of almost all of the employees at this entire company - so I am in a leadership role. Does anyone have any advice on how to reveal this to the staff? I feel so uncomfortable sharing this news with professional coworker types. Also, I was waiting till I have good news about revenue or a big project to share so they have confidence in me as a leader, when I tell them the news, but so far, no business good-news. Any tips? Mass email blast seems too impersonal. :(