Scared to tell my parents !!

Michelle • 33 year old from Australia , currently pregnant with baby #4 a boy..miss 7 mr 5 miss 1 and prince due 26/01/17
So this is baby #4 for me and #2 for now partner, he was a bit MIA whith our little girl while I was pregnant she is now 9 months  , but has changed so much and things are great between us , we have told his family we are expecting again and there sooooo happy , my parents on the other hand we have not told as I know they will be all omg why why why with him !! Now don't get me wrong they will be happy eventually , but how can I do it to make them not yell and scream at me ?