Production will indeed be affected by Black Widow actress, Scarlet Johansson's recently revealed pregnancy. The plans are for the studio to “fast-track her scenes” once she returns from promoting Captain America: The Winter Soldier and will begin filming abroad on April 5th.
So it appears we can all let out a big sigh of relief that filming will not be delayed and we can still expect a fully involved Black Widow.
The Avengers: Age of Ultron opens May 1, 2015