Abducted by Aliens?!?

Unless you are/have modded your game to allow female, there shouldn't be a pregnancy from alien abduction for a female sim if that helps. Sometimes alien abduction DOES happen randomly from any skilling up, I've found, but it seems extremely rare in my game. (I think its only happened twice in my game since GTW was launched, and then it's only been female sims and no babies were produced from them.) If you just feel the need to restart to get it out of her save you can but they don't really have a "memory" timeline in Sims 4 that I've found so it shouldn't affect your game overly that she has been abducted. In my saves where they were, it did not result in aliens populating/overpopulating my world either. I had to actively seek out alien partners through the science career or going to an alien night at a bar to get alien children.

Hope that helps you in some way.