Estrogen is called the female hormone, as it plays an important role in shaping the female body and is required for pregnancy. It also has beneficial effects on the bones, heart and is responsible for the lining of the uterus, vagina and urinary system. Progesterone another female hormone along with estrogen regulates the changes in the uterine lining responsible for menstruation and helps maintain pregnancy. Prior to menopause more than 90% of estrogen comes from the ovaries. Other organs like adrenal glands, liver, kidney and fat cells also make small amount of estrogen.
With aging the ovarian stroma is exhausted of the ovarian follicles /eggs and after menopause one can safely say that there are no remaining ovarian follicles and estrogen and progesterone levels fluctuate and decrease. Despite reactive increase of FSH and LH (hormones which stimulate the ovary) the ovaries are unable to produce estrogen and progesterone in sufficient amounts. Menopausal symptoms are largely felt due to sudden withdrawal of estrogen.