How to deal with not telling ur mother ur pregnant?

I wish I could tell my mom I'm pregnant but I don't because one I don't wanna be judged and get a lecture since I'm 20 and don't have my GED yet (was homeschooled) but second the big one is cause I was sexualy abused by my step dad from when I was a kid up into my teens and my mother never believed me and was involved the first time it happened and I moved away cause the abuse had started again and I didn't wanna deal with it. And so I think it's just mean to say "hey ur gonna have a grand kid but I won't let u see it" cause like what's the point right??? Rn I'm married and live with my husband and his family and my mother in law is very lovely and is almost like a mother figure to me since I don't have mine to talk to about the pregnancy. But only my husband and his 2 sisters know what happened to me, and I get reminded of it when my in laws ask why I haven't told my parents yet. I say idk but I know and my husband knows exactly why. I'm not close to my mother but I wanna tell her but I know I can't, it's just a little hard sometimes.