What to do about my sister in law...

So my sister in law (husband's sister) HATES children and acts as if other people having children is her own personal burden. I just know she will overreact to me being pregnant. My husband doesn't even want to ever tell her. Last time I was pregnant she told me to get an abortion REPEATEDLY and as late as 20 weeks! When she found out my best friend was pregnant she was very judgmental and nasty about it even though it was none of her business. The problem is that she lives with us and she helps with bills a lot so we kind of need her here. She isn't a bad person, she just HATES kids. How do we tell her that we are going to have another baby? I just know how bad the reaction will be and I don't know if I can take the hurtful things she will say.

I also want to add that she is never bad to my son and kicking her out is not an option. I am just worried about telling her.