You'll see a lot of closeups, overcoats, and loose, baggy clothing with yes, limited action scenes. Killer Frost's new outfit will also go a long way towards disguising the baby bump, since black is a naturally slimming color. It's the show's only option, since I can't see how they'd write Danielle's pregnancy in without a time jump AND an explanation as to who the baby daddy is.
And yes, she'll be just starting to show now. Actresses usually announce after the first trimester has passed, so it would be impossible NOT to tell that she's pregnant at this stage.