[1] Mammoplasia occurs normally during puberty and pregnancy in women, as well as during certain periods of the menstrual cycle.

[4] When it occurs in females and is extremely excessive, it is called macromastia (also known as gigantomastia or breast hypertrophy) and is similarly considered to be pathological.

[9][10] During the luteal phase (latter half) of the menstrual cycle, due to increased mammary blood flow and/or premenstrual fluid retention caused by high circulating concentrations of estrogen and/or progesterone, the breasts temporarily increase in size, and this is experienced by women as fullness, heaviness, swollenness, and a tingling sensation.

[11][12] Mammoplasia can be an effect or side effect of various drugs, including estrogens,[2][13] antiandrogens such as spironolactone,[14] cyproterone acetate,[15] bicalutamide,[16][17] and finasteride,[18][19] growth hormone,[20][21] and drugs that elevate prolactin levels such as D2 receptor antagonists like antipsychotics (e.g., risperidone), metoclopramide, and domperidone[22][23] and certain antidepressants like selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs).

[22] Other drugs that have been associated with mammoplasia include D-penicillamine, bucillamine, neothetazone, ciclosporin, indinavir, marijuana, and cimetidine.