Friend is a blabbermouth. Should I tell her I'm pregnant??

I'm 15 weeks pregnant and only a close bunch of people know about it. I'm finding out the gender next week but I am moving the week after and right now I do not have the time to make the official announcement which I have postponed until 20 weeks due to my older kids school schedules and work and moving. Now I have a friend that I consider close but she is a blabber mouth. She goes around talking about everyone and everything. Otherwise she is a very caring person that I really like and get along with. I have not told her yet and was planning on not telling her until the announcement but now I'm worried if she will be upset that I didn't tell her personally. There is no point in telling her to keep it quiet until the official announcement as she won't be able to do it. She will keep on making remarks pointing towards baby infront of people and that makes me uncomfortable. What should I do ???