I'm sure she isn't doing it to hurt you if she is already a talker like you said she is probably just excited and letting it slip out ....I can see why its frustrating but try not to let it get you all worked up especially if you had miscarried before

Yup that's really all I can do is not tell her anymore I told her it upset me and she said she slipped up and didn't mean it which I explained now my father in law was going to know along with everyone else and she didn't seemed like she was bothered by it obv of course bc she's not the one who's scared the whole thing has me so fed up to where I'm like fuck it I'm not telling anybody shit no more

Or maybe just tell her things in smaller detail than you normally would? May be no way of keeping her from gossiping.

Then that's just very rude and inconsiderate. That would infuriate me. Talk to her in person with your husband there and get her to understand. If she can't see how it bothers you, I'm sorry to say but you might have to hold back on talking to her about things. It sucks when someone doesn't understand how you feel when it seriously matters.

It pisses me off so bad bc she knows how scared I am after what I've been through with my losses and I wanted to tell my nan in a special way once I had my ultrasound but she just can't help but run and tell people including my nan it's like he doesn't understand why I'm so mad I mean she's always been this way it's just who she is she gossips

Tell him you were really hoping to tell everyone after the first trimester and that you don't appreciate her going against your wishes.

My mom ran her mouth to her friends at work. There is nothing you can really do. I did try to explain to her that we were waiting to make sure the baby was ok before we told people. Lucky for her we were good. But I was mad too. At least no one Facebook knew until we were ready.