Even if there is no limit, eventually, her breast implants will weight so much that she won't be able to lay down her breasts in any one position for more than a few minutes without cutting off circulation. By the time a woman's breast become this large, she probably won't be able to walk.
But I came up with a solution......
Me and my girlfriend (well, mostly she) came up with another solution. Which is to fill a normal implant with
Aerogel instead of saline.
Aerogel is 0.2% heavier then air, so nearly weightless (yes geeks, I meant in relation to our atmosphere). Ofcourse, you will need a thicker implant shell to separate the Aerogel with breast tissue.
Also, aerogel is really rigid, to insert it as one block will give a really big scar. Inserting it as really small particles (like a rice bag) would make it possible to fill the implant after insertion, but the empty space between the particles cannot be normal air (if the implant ruptures, and air gets into a blood stream.... the results would be catastrophic), so you'll need saline to fill the void between the particles.
With some calculations it would mean that Aerogel implants would weigh about 10-15% of a normal saline implant of that size.
Still, we need to find a company that could make implants that use aerogel as a filler.
Ps. we've also discussed some non-toxic gas as a filler, like a true balloon, but that won't be any good. Just think of this, if you drive up a mountain, your ears start to get painful, because the air pressure outside is lower, because the air is less dense. It means that the dense air in your ear still needs to expand to be at a similar level. The same thing would happen to that gas in the implant. So.... it would grow. Now, that may be cool to some degree, but if you imagine a plane... the cabin is always pressurized so you wouldn't notice much, but what happens if the plane loses pressure?
It will go so fast the implants expand so fast it'll rupture the skin and well... literally explode.