Tony- you and Tony built a small iron man suit and put it in the common room in stark tower. Nat was the first one to figure out that you were pregnant.
Clint- you bought a child bow and arrow you showed it to Clint who became very excited and started to ran around stark tower telling every one.
Bruce- you had no idea how you were going to tell any even bruce. You just got a pair a shorts that match the ones hulk wears and decided to just tell everybody at the same time
Thor- you told Thor normally and he went around stark tower telling every one you were pregnant
Nat- you and Nat planed to adopt so to announce it to the boy's you took a picture of you and Nat in your cat suits holding a cat suit in a kid's size and under the picture you put "be ready we're getting another assassin". All the guys laughed and graduated you
Steve- once you told Steve he got excited and ask how you're going to tell your friends you said by getting a captain America suit for the baby and show them that.