Confused

I don’t think I’m understanding this correctly at all.

So say you’re RH- had the shot first pregnancy then not after delivery because baby was - too. Great, perfect.

So you’re pregnant again. Does RH- effect this pregnancy or the following if you decide to have more kids after this pregnancy. A conversation led to this and I don’t get it. Call me dumb whatever I just need someone to simplify it. Just confused about it, that’s all.