The size of the uterus is determined by age and the presence or absence of appropriate pathologies. Usually the uterus is small before puberty, but with the onset of puberty, the uterus will increase in size under the stimulation of estrogen and progesterone. The normal size of the uterus in reproductive age is 7-8cm in length, 4-5cm in width, and 2-3cm in thickness, and the uterus shrinks accordingly after menopause, which is a normal physiological change. In pathological conditions due to uterine fibroids, adenomyosis or other pathological conditions, the uterus will enlarge accordingly, even unevenly.