How to tell my parents I'm pregnant

My sister already has 3 kids (1 my mom has, 1 got adopted, and she has the last one) and just announced last month that she was pregnant again. I just got my BFP and this will be the first happy (I hope) pregnancy in the family. My husband's parents are going to be over the moon but I'm worried about mine not being as happy because of the drama with my sister. I need a cute way to tell them so that they're happy for me and not upset.