A birthed quilt is one that you layer with right sides together, sew around all 4 sides - leaving a gap to turn through, then turn it right side out and finish the gap you used to turn it.
I also quilted these from the center out. My quilts done this way are a bit puffier, but ... for my stage at the time ... they worked. I did them because I was scared of finishing them any other way. Now ... at a later stage ... I think they are more trouble - and harder to get right - than the other way!