What would you do? Friendship story

I know this seems highschoolish but I am pissed and dont want to make situations worse. Long story short, I prefered to keep my pregnancy private a bit longer, but had two best friends that I wanted to share the news with. I told one of them specifically the news and asked her to please not tell anyone else. She agreed and we talked for more than an hour how its best to keep these things private, etc etc. The NEXT day, I discover that someone we know told her husband which ended up calling my husband to congratulate him. The best friend and the wife of the guy that called are relatives, so my best friend TOLD! This is my special news to share. I am pissed that after I told her not to tell, she told. I am not upset necessarily that she told this specific person, but if she told one, she could tell 100, there's no guarantee. I am worried to confront her, and it will only create problems and drama between them and could impact the friendship between the husbands as well. Would you just forget about it? At least try, or confront her no matter the outcome/drama.