Menstruation and Menstrual Disorders

Menstruation (men-stroo-AY-shun) is the discharge of the blood-enriched lining of the uterus. Menstruation normally occurs in females who are physically mature enough to bear children. Most girls have their first period between the ages of 9 and 16. Menstruation ceases during pregnancy and with the onset of menopause. Because it usually occurs at about four-week intervals, it is often called the monthly period.

Menstrual (MEN-stroo-al) disorders result in abnormal menstrual periods. Usually, these disorders occur when the hormones * that control menstruation are out of balance. In some cases, however, another medical problem is the cause. Menstrual disorders include pain during periods; changes in the length of the menstrual cycle; and heavy, prolonged, or too-frequent periods.

Kim's Story

* to find out why Kim has not had her period.

Anatomy of the female reproductive system, including an unfertilized egg (ovum) in one of the fallopian tubes.

Anatomy of the female reproductive system, including an unfertilized egg (ovum) in one of the fallopian tubes.
Illustration by Frank Forney. © 2016 Cengage Learning®.

The doctor examined Kim and asked her a number of family history and health questions, including questions about sports and how long she has been playing. The doctor told Kim that she probably had nothing to worry about; some girls just get their period later than others. Just to be sure, the doctor ordered some blood tests that would show if Kim had a medical condition affecting her menstrual cycle. The tests showed she was indeed fine, and three months later, Kim got her first period.

What Are the Menstrual Cycle and Menstruation?

The menstrual cycle is a normal part of being a healthy female of reproductive age. About once per month in this cycle, the female's reproductive system yields an egg that is ready to be fertilized, as well as the environment in which the fertilized egg can develop. This environment is the blood-rich lining of the uterus * (YOO-ter-us). If the egg is not fertilized, menstruation, also called menses (MEN-seez), occurs. During menstruation, the uterine lining sheds, resulting in blood and tissue being expelled from the body.

The female reproductive system, located in the abdomen *

The 28-day menstrual cycle, showing changes in the thickness of the endometrial lining.

The 28-day menstrual cycle, showing changes in the thickness of the endometrial lining.
Illustration by Frank Forney. © 2016 Cengage Learning®.

Eggs move through the fallopian tubes to the uterus, which provides the environment in which a fertilized egg can grow and develop into a fetus. If the egg is not fertilized, the lining of the uterus sheds, and blood and tissue fragments exit the uterus through its opening, the cervix, and travel through the vagina to the outside of the body.

The hormonal interaction in a typical menstrual cycle

The following are the major events in a typical menstrual cycle.

* .
  • Days 17 to 27: If the egg is not fertilized, hormone levels decrease.
  • Day 28: The endometrium begins to break down, and menstruation begins. Cells in the uterine lining produce the hormone prostaglandin (pros-ta-GLAN-din), which causes blood vessels to narrow, slows the supply of oxygen to the uterus, and causes the muscles of the uterus to contract. This process helps to expel the blood and tissue of the uterine lining.
  • What Is Normal?

    In a woman who is not pregnant, the menstrual cycle—calculated from the first day of one period to the first day of the next—occurs approximately every 28 days. However, the length of the cycle can vary from 21 to 35 days in normal, healthy girls and women. Usually, bleeding lasts for several days, which is the basis for the term menstrual “period.” A woman wears a pad in her underwear or a tampon inserted into the vagina to absorb the blood, which typically amounts to two to eight tablespoons during an entire monthly period. Normally, menstrual blood does not clot. Women who experience clotting should mention it to their doctor.

    The first time a young girl gets her period is called menarche (MENar-kee). Some girls are scared of menarche, whereas others are eager to experience it. In the United States, the average age when menarche occurs is about 12.5 years of age, but some girls start menstruating at 10 or younger and others at 16 or older. After menarche, a woman usually will get her period for 30 to 40 years, until she goes through menopause * .

    A huge variation exists among women in the length and duration of the menstrual cycle and in whether they bleed a lot or a little. Some women have a period every 23 days; others have a period every 35 days. Some periods last three days, whereas others last seven. And some women use three tampons or pads per day, whereas others need several more. Because of this wide range, determining if a woman has a menstrual disorder can be difficult. It requires that a woman knows her own body and what is normal for her.

    What Are Menstrual Disorders?

    Disorders in menstrual cycle length

    Amenorrhea (a-men-o-REE-a) means “no menstrual periods.” Primary amenorrhea means not having a first period by the time a girl is 16 years old. Secondary amenorrhea occurs when a woman or girl stops getting her monthly period.

    A related problem is oligomenorrhea (OL-i-go-men-o-REE-a), which occurs when menstrual periods are more than 35 days apart. Once doctors diagnose problems with menstrual cycle length, they then try to find out what is causing it.

    Kim's story provides an example of primary amenorrhea. This condition may be caused by a hormonal imbalance or a developmental problem. Young female athletes often experience primary or secondary amenorrhea or both. Strenuous exercise seems to lower estrogen levels, thus causing periods to stop.

    Shelly, a 25-year-old woman who usually gets her periods like clockwork, stopped having her period for three months. Her doctor first ordered a pregnancy test. It was a surprise to Shelly and her husband to learn she was pregnant. Pregnancy is the most common cause of amenorrhea in women in their reproductive years. A little while after the baby was born, Shelly resumed her regular menstrual cycle.

    When Anne turned 48, the amount of time between her periods started getting longer and longer. When she did not get her period for four months, she went to see her doctor. The doctor examined Anne and did some tests. Anne learned that her amenorrhea was caused by approaching menopause, the natural time in a woman's life when she no longer has periods and cannot become pregnant anymore.

    Medical problems, such as cysts (fluid-filled sacs) in the ovaries, abnormal growths or tumors * in the reproductive organs, anorexia nervosa * , and diabetes * , can also cause amenorrhea or oligomenorrhea.

    Altered hormone levels can cause anovulation (an-ov-yoo-LAY-shun), which occurs when ovulation does not take place, which in turn often causes amenorrhea. Hormones are affected when a woman exercises too much, loses or gains a lot of weight, is stressed, is breast-feeding a baby, or has an eating disorder * . All of these situations can lead to amenorrhea.

    Bleeding disorders

    In 80 percent of women with menorrhagia, the cause is either a hormone imbalance or the presence of fibroids (FY-broidz), which are abnormal growths in the uterus. Other causes of menorrhagia include the following:

    Dysfunctional uterine bleeding (DUB) is another name for menorrhagia and other bleeding disorders that are caused by hormonal imbalances. Often, DUB occurs because of anovulation or when estrogen and progesterone are out of balance. Without proper hormonal cues, normal monthly shedding of the uterine lining does not occur, and the endometrium continues building up. The abnormally thick endometrium eventually starts to break down and results in heavy and prolonged bleeding. DUB is common in teenagers, whose hormones have not yet been finetuned and who often do not ovulate regularly. Anovulation is also common in women about to go through menopause.

    Painful periods

    Linda's school attendance was affected by her menstrual periods. For four months in a row, Linda went home sick from school each time she started her period. Linda was not faking it; she went home to bed with a backache and severe cramps, only getting up when she thought she might have to vomit.

    Linda suffers from dysmenorrhea (dis-men-o-REE-a), or painful periods. Almost every woman has this condition at some time in her life. The symptoms of dysmenorrhea range from mild, uncomfortable cramps to abdominal pain, a sore back, nausea, and vomiting. Linda has primary dysmenorrhea, which means painful periods with no underlying medical disease. This type of dysmenorrhea is very common, especially among teenagers. The symptoms result from the hormone prostaglandin, which is released by the cells that are being shed from the uterus.

    Secondary dysmenorrhea is caused by medical conditions such as polyps *

    Can a Girl or Woman Exercise Too Much?

    How much estrogen a woman's body produces appears to be linked to her level of body fat. Gymnasts, ballerinas, and other athletes who regularly take part in strenuous exercise typically do not have much body fat and do not make much estrogen. If their hormone production is low enough, they might not get their first period until they are 16 or 17. Other young athletes who have normal periods for a while may develop amenorrhea when they resume strenuous exercise.

    Because bone mass is linked to the level of estrogen in the body, some scientists suggest that even a few years of amenorrhea, especially during a girl's teens, can have lasting effects on bone formation or contribute to excessive bone loss. Young athletes should see their doctor if they experience a menstrual disorder. Diet and hormone therapy may fix the immediate problem and have a positive effect long into the future.

    To ensure good bone health in general, doctors may recommend the following: exercising daily; maintaining a healthy, not-too-thin weight; getting enough calcium and vitamin D every day; managing stress, because stress can actually cause bone loss; staying away from cigarettes; and cutting back or eliminating caffeine from the diet. For girls with menstrual disorders, a doctor may also prescribe progesterone supplements. This hormone stimulates cells, called osteoblasts, to build new bone.

    Infection of the endometrium causes another type of pain that accompanies menstrual periods. This pain, seen in pelvic inflammatory disease (PID), needs rapid diagnosis and medical treatment.

    Premenstrual syndrome

    Every month, Stacy can tell her period is a week away by three signs: Her skin breaks out, her lower back begins to ache, and her breasts feel sore. Her friend Sonya experiences a different set of symptoms: She feels bloated, is incredibly tired, has bad headaches, and feels depressed and grumpy.

    Stacy and Sonya have premenstrual syndrome, or PMS, which is a set of symptoms that includes both physical and emotional symptoms. Most women with PMS have particular symptoms that occur each month at the same time. Fortunately, the symptoms disappear when the period begins. No one knows for sure what causes PMS, but most scientists agree that it is linked to hormones. PMS symptoms appear during the second half of the menstrual cycle, after ovulation has taken place and when progesterone levels are highest. Health professionals may recommend one or more of the following to treat the symptoms of PMS:

    At one time, doctors frequently prescribed birth control pills to treat PMS. Studies showed, however, that they were not widely effective. In addition, the estrogen in birth control pills can increase the risk of uterine cancer if it is not combined with another hormone, progestin, and studies have shown that progestin alone does not treat PMS symptoms.

    Treatment for Menstrual Disorders

    * , where instruments are inserted into the body through a small incision to take a direct look at the internal organs.

    Literal Meanings of Menstrual Terms

    Many words used to describe menstruation and menstrual disorders come from Latin and Greek. The following are a few:

    • Menses comes from the Latin word “mensis,” which means month. “Mensis” also derives from the Greek word “mene” for moon; the moon travels around the sun approximately once every 28 days, about the length of a month.
    • Menarche, a girl's first period, comes from “mensis” and “archaios,” meaning “from the beginning.”
    • Menopause, or the end of monthly periods, comes from “mensis” and “pauses,” meaning “to cease.”
    • Menorrhagia means “heavy or prolonged bleeding” and is derived from “mensis” and “rhegynein,” meaning “to burst forth.”
    • Menorrhea comes from “mensis” and “rhoia,” meaning “to flow” and refers to the “normal flow” of blood and tissue from the uterus during a menstrual period, also called menses and menstruation.
    • The prefix “a-” means “not,” and amenorrhea is the “cessation of menses.” The prefix “dys-” means “bad or painful,” and dysmenorrhea means “painful periods.” The prefix “oligo-” means “little or few,” and oligomenorrhea means having “infrequent periods.” The prefix “poly-” means “many,” and polymenorrhea means “periods that come too frequently.”

    For all menstrual disorders, treatment depends on the underlying cause. Therefore, a woman should see a doctor if her menstrual cycle seems abnormal.

    Hormonal imbalance

    When a hormonal imbalance is the cause of a menstrual disorder, hormone therapy often helps menstrual cycles return to normal. Hormone therapy includes taking birth control pills, mixtures of estrogen and progesterone, or just progesterone.

    Dysmenorrhea and PMS

    Products such as ibuprofen * and naproxen (na-PROKS-en) suppress prostaglandin and are helpful in treating dysmenorrhea. Over-the-counter products to relieve menstrual cramps and bloating help some women with PMS. Birth control pills also reduce painful periods in some women, as does exercise.

    Endometriosis and other conditions

    For some women with endometriosis, the doctor may prescribe medicines to relieve symptoms. Women with severe endometriosis may need surgery to remove implants.

    Methods of eliminating severe menstrual disorders include destroying the endometrial tissue in the uterus or removing the uterus (and sometimes also the ovaries) in a procedure known as hysterectomy (hister-EK-to-mee). This treatment is better for older women who are past childbearing years. This is not a treatment for younger women who want to have children.

    For medical conditions, such as fibroids, polyps, or cancer, a woman may need surgery and other treatments to correct the problem.

    See also Anorexia Nervosa • Endometriosis • Infertility • Menopause • Pelvic Inflammatory Disease (PID) • Puberty and Sexual Development • Pregnancy


    Books and Articles

    Marshburn, Paul, and Bradley Hurst. (eds.) Disorders of Menstruation. Hoboken, NJ: Wiley-Blackwell, 2011.

    Natterson, Cara. The Care and Keeping of You 2: The Body Book for Older Girls. Middleton, WI: American Girl Publishing, 2013.

    Thorpe, JR. “What the Age You Got Your First Period Says About You, According to Science.” Bustle. (August 27, 2015). (accessed November 18, 2015).


    Eunice Kennedy Shriver National Institute of Child Health and Human Development. “Menstruation and Menstrual Problems: Overview.” U.S. Department of Health and Human Services, National Institutes of Health.

    MedlinePlus. “Menstruation.” U.S. National Library of Medicine, National Institutes of Health. (accessed March 7, 2016).

    Merck Manual: Consumer Version. “Menstrual Cycle.” (accessed November 18, 2015). . “Menstruation and the Menstrual Cycle Fact Sheet.” Office on Women's Health, U.S. Department of Health and Human Services. (accessed March 7, 2016).


    American Congress of Obstetricians and Gynecologists. PO Box 70620, Washington, DC 20024. Toll-free: 800-673-8444. Website: (accessed March 7, 2016).

    American Pregnancy Association. 1431 Greenway Dr., Suite 800, Irving, TX 75038. Telephone: 972-550-0140. Website: (accessed March 7, 2016).

    American Society for Reproductive Medicine. 1209 Montgomery Hwy., Birmingham, AL 35216. Telephone: 205-978-5000. Website: (accessed March 7, 2016).

    * hormones are chemical substances that are produced by various glands and sent into the bloodstream carrying messages that have certain effects on other parts of the body.

    * gynecologist (gy-ne-KOL-o-jist) is a doctor who specializes in the reproductive system of women.

    * uterus (YOO-teh-rus) is the muscular, pear-shaped internal organ in a woman where a baby develops until birth.

    * abdomen (AB-do-men), commonly called the belly, is the portion of the body between the thorax (THOR-aks) and the pelvis.

    * embryo (EM-bree-o), in humans, is the developing organism from the end of the second week after fertilization to the end of the eighth week.

    * menopause (MEN-o-pawz) is the natural decline in reproductive hormones and the end of menstruation.

    * tumors (TOO-morz) are abnormal growths of body tissue that have no known cause or physiologic purpose. Tumors may or may not be cancerous.

    * anorexia nervosa (an-o-REKse-a ner-VO-sa) is an emotional disorder characterized by dread of gaining weight, leading to selfstarvation and dangerous loss of weight and malnutrition.

    * diabetes (dye-uh-BEE-teez) is a condition in which the body's pancreas does not produce enough insulin or the body cannot use the insulin it makes effectively, resulting in increased levels of sugar in the blood. This can lead to increased urination, dehydration, weight loss, weakness, and a number of other symptoms and complications related to chemical imbalances within the body.

    * eating disorder is a condition in which a person's eating behaviors and food habits are so unbalanced that they cause physical and emotional problems.

    * liver is a large organ located beneath the ribs on the right side of the body. The liver performs numerous digestive and chemical functions essential for health.

    * kidney is one of the pair of organs that filter blood and remove waste products and excess water from the body in the form of urine.

    * polyps (PAH-lips) are bumps or growths usually on the lining or surface of a body part (such as the nose or intestine). Their size can range from tiny to large enough to cause pain or obstruction. They may be harmless, but they also may be cancerous.

    * antidepressant medications are used for the treatment and pre

    * laparoscopy (lap-uh-ROS-kuhpee), also called minimally invasive surgery, is a type of surgery in which a small fiberoptic instrument is inserted through a very small incision to examine the inside of the abdomen or remove small amounts of tissue.

    * ibuprofen (eye-bew-PRO-fin) is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce fever and relieve pain or inflammation.

    Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

    (MLA 8th Edition)