The body manufactures three main kinds of estrogen: estradiol, estrone, and estriol. Estrogens are promoters of tissue growth, stimulating the proliferation of cells in the reproductive organs of women, particularly in the endometrium, the blood-rich lining of the uterus that is shed during menstruation. The collective effect of estrogen (the “estrogen effect”) in a woman’s body can be estimated through evaluation of the squamous cell layer that lines the vagina in a test known as a maturation index.
