Should I approach or leave her alone

So I’m currently pregnant and my boyfriend has a child. His ex girlfriend has mental health issues. She’s got PTSD,bipolar disorder,depression and an eating disorder. One moment she’s all fine with me and one moment she tells me she hopes I wake up in a pool full of blood and I have a miscarriage that it’s the most painful thing I have to go through. This stems from her getting pregnant with him and she had an abortion. So seeing me pregnant and hearing about it triggers her. Which in result has made me had to hide it and be scared because I don’t want to get attacked. I’ve had multiple miscarriages in the past and it means a lot to have this baby. She will always be in my life but idk what to anymore.