Not only may you find aa problem by washing after quilting, but those horrid little threads that you have carefully clipped on the back of the quilt grow when you wash and you'll find a lot more to clip! Also, the quilt relaxes into shape when washed and it helps hid that oooops. Besides, am I the only quilter that has one end hit the floor while working on the other?
Use either the "delicate", "handwash" never the "regular" cycle! If you have a front loader (like I got this year when the oldie died) you are one of the lucky ones!