the smaller side can be augmented with a prosthesis. The larger side with more sagging could be lifted with reduction in the size of the areola, by reshaping the breast with basically a skin only procedure ( no implant ). the lift could be undone by pregnancy and breast feeding. you may want to defer until after your pregnancies.. you could alternatively leave the larger breast alone but only augment the smaller breast, accepting the shape difference until after all pregnancies. I would reccommend one or more plastic surgical consultations

William Jervis