• Basics

    Menopause is a natural part of aging. It refers to the time in a woman's life when her periods (menses) stop and she is no longer fertile.

    Every woman will experience menopause, or the cessation of her period (menses). This occurs when the ovaries stop functioning. The ovaries are the organs that store and release eggs, and they play a role in hormone levels in the body. When the ovaries stop working, a woman is no longer fertile.

    A woman is said to be in menopause when she has not had a period for 12 months, she has symptoms of menopause such as hot flashes, and no other cause can be established. Not menstruating for an entire year after the age of 45 is the typical definition of menopause. No tests can predict when menopause will happen or how long menopause symptoms may last.

    The age in which women experience menopause varies greatly. Most women reach menopause at around 51 years of age.

    The average age at which a woman reaches menopause is 51 years, but the range is between 45 and 58 years. Although the average time for transition into menopause is 5 years, it can take anywhere from 2 to 8 years. However, menopause can occur abruptly in women of any age who have had their ovaries surgically removed.

  • Causes

    Menopause happens due to a sharp decrease of female hormones in the body. Scientists do not know what triggers the ovaries to stop working and hormone levels to change Figure 01.

    A woman's menstrual cycle is influenced by a complex system of hormones. It is a change in these hormones that causes menopause to occur.

    Two substances - called luteinizing hormone (LH) and follicle-stimulating hormone (FSH) - start the process of the monthly menstrual cycle. They are released into the bloodstream by the brain's pituitary gland, and signal the ovaries in the reproductive system to produce the female sex hormones estrogen and progesterone. Estrogen and progesterone work to prepare a woman's body for possible pregnancy. They prepare an egg for release from the ovaries and cause the lining of the uterus (womb) to thicken so it is ready to provide a good environment should the egg be fertilized and pregnancy occur. If the egg is not fertilized and no pregnancy occurs, hormone levels drop and menstruation begins. During menstruation, the uterine lining is shed and expelled from the body, resulting in bleeding from the vagina. The process then begins all over again.

    With age, the ovaries become less receptive to commands from the pituitary gland. This causes the pituitary gland to produce more LH and FSH, the ovaries secrete less and less estrogen and progesterone, and the menstrual cycle eventually comes to a halt.

    Click to enlarge: Female reproductive anatomy

    Figure 01. Female reproductive anatomy

    Certain factors can influence the age at which menopause begins.

    The age which a woman begins menopause can be influenced by certain factors.

    Cigarette smoking: Smokers experience menopause an average of 1 year earlier than nonsmokers.

    Family history: Genetics also plays a role in the age a woman is likely to experience menopause. Mothers and daughters tend to experience menopause at similar ages.

    Chemotherapy: Chemotherapy and radiation therapy increase the risk of premature menopause.

    Surgery: Hysterectomy (surgical removal of the uterus) alone does not typically trigger early menopause; however, menstrual bleeding will stop after a hysterectomy. If both ovaries are removed (bilateral oophorectomy), menopause starts immediately after surgery, regardless of your age.

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