Announcing pregnancy to others?

My husband's brother is getting married October 8th. We don't want to take away from the bride and groom's attention or big day so we are waiting until after the wedding to tell our families. My question is, how long after should we wait? I'm just trying to avoid drama with the bride as she can be very.. witchy.. about things. She yelled at me on Christmas day one year for planning to invite someone to our wedding she didn't like. So what amount of time should we wait?