In this one I'd say that she's just top heavy and gynoid bodies tend to have a bit of fat around the hip area with a pronounced pouch and the artist tried to portray that (Some of the rolls do not make sense to me, though. There are also some other anatomical oddities). Her tummy in this illustration however is still quite sucked in and, rather than overweight, for me she's more muscular and that makes her upper half look wider which is very likely the result of somebody still learning to draw this kind of body.
However even in the original work she is still a bit on the bigger side (not necessarily overweight but by default more "mature" looking) when it comes to her structure as a whole so I don't see the issue as a bit more fat in the body is normal as the result of estrogen.