I'm Scared To Tell My Sister I'm Pregnant

I'm pregnant with baby #8. My sister has been trying for six years. She's had 5 miscarriages and three failed rounds of IVF. I'm scared to tell her because last pregnancy when I told her she got so mad she threw a lamp at me and it hit me in the head. My husband never forgave her for that, but I just try to understand her feelings. I just don't know how to go about telling her. Any advice?