In premenopausal women, the uterine wall, or endometrium, thickens as estrogen levels increase during the menstrual cycle, notes Dr. Martee Hensley for Everyday Health. Endometrial hyperplasia, a condition resulting from excess estrogen without progesterone, also causes a thickened uterine wall, says the American Congress of Obstetricians and Gynecologists.
In premenopausal women, the thickness of the uterine wall varies in response to hormones produced during the menstrual cycle, states the American Congress of Obstetricians and Gynecologists. In the initial part of the cycle, estrogen causes the endometrium to thicken as the uterus prepares for pregnancy. Ovulation, which occurs in the middle of the cycle, triggers an increase in levels of progesterone; this hormone prepares the uterine wall to nurture a fertilized egg. If the egg is not fertilized, progesterone and estrogen levels decline and cause shedding of the endometrium during menstruation.
In postmenopausal women, the thickness of the uterine wall does not vary due to the cessation of the menstrual cycle, explains Dr. Hensley. Postmenopausal endometrial thickening is thus atypical and an indicator of continued estrogen stimulation. Such thickening is usually the result of taking certain medications or ongoing estrogen production. Because postmenopausal uterine wall thickening may be an indicator of cancer, women with the condition should seek medical attention.
Endometrial cancer causes aberrations in growth rates of the uterine wall, according to Mayo Clinic. Physicians suspect that such uncontrolled proliferation arises from impairment of the normal uterine cell death process by genetic mutation. This results in cancerous uterine tumors that may eventually spread to surrounding tissue.