Band-assisted pull-ups are one of our favorite modifications for those who can't yet perform pull-ups, or those who can only perform a few and are looking to add volume.
Pull-ups are a total body exercise that are particularly intense on your core. Molly Galbraith offers tips in this video on when it's a good time (and when it's not!) to include this exercise in your program for pregnant moms-to-be, along with coaching cues to help make this movement strong and stable.