Going by the "fullness" on the top part I am saying implants.
The reality of the situation is that after 18 or so "major growth spurts" are RARE, really rare.
Even the growth spurts that are the results of pregnancy way more often that not do not last and normally return to with a cup size of where they started, some times even smaller.
The only real exception is when the woman in question does NOT loose all/any of the "baby weight" and as we can see that does not look be the case with her, in addition to the fact that I do not know one way of the other if she has yet to have a kid.