I don't know what to do.

I recently found out in 12 weeks pregnant, with my rainbow baby. my bestfriend has been trying for 2 years, and nothing has worked for her. I'm debating on telling her, cause I know it's gonna kill her, and I don't want her upset. I know she'll be happy for me, and love her godchild more than anything, I just hate seeing her get so sad when she finds stuff like this out. Any advice?