The average woman's uterus is roughly three inches long, two inches wide and one inch deep. The size of a woman's uterus may be larger if she has had children.
The uterus is composed of both the myometrium and the endometrium. The myometrium is the muscular layer of the uterus that allows it to contract during a woman's menstrual cycle and during labor. The endometrium is the smooth, inner layer of the uterus that contains a thick layer of tissue that is shed each month during a woman's menstrual cycle. If a woman becomes pregnant, the zygote implants itself in the endometrium where it receives nourishment.