Understanding Polymenorrhea: A Type of Abnormal Uterine Bleeding

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Polymenorrhea describes a menstrual cycle abnormality in which a woman experiences regular bleeding at intervals of less than 21 days.

To put this in perspective, a normal menstrual cycle for an adult woman is 21 days to 37 days long.

When researching the term "polymenorrhea" or "short menstrual cycle," you may have come across the word "abnormal uterine bleeding." This is because the term polymenorrhea (and other terms associated with abnormal menstrual patterns) are generally cast under this umbrella term.

Overview of Abnormal Uterine Bleeding

According to the American College of Obstetricians and Gynecologists (ACOG), abnormal uterine bleeding is defined as bleeding from the uterus that is abnormal in regularity, volume, frequency, or duration. The bleeding may be acute or chronic and occurs in non-pregnant women. 

Besides polymenorrhea, other causes of abnormal uterine bleeding include:

  • Oligomenorrhea: Menstrual cycle length that is greater than 37 days
  • Amenorrhea: No period for six months 
  • Menorrhagia: Heavy bleeding during your periods
  • Metorrhagia: Bleeding or spotting in between your periods
  • Menometrorrhagia: Longer duration of menstrual bleeding that occurs at unpredictable intervals
  • Postmenopausal bleeding: Bleeding that happens more than 12 months after a woman's last menstrual cycle
  • Postcoital bleeding: Bleeding or spotting after sex

Potential Causes of Polymenorrhea and Other Types of AUB

There are many possible causes of abnormal uterine bleeding, which is why it's important to see your doctor.

In addition to taking a thorough medical history, your gynecologist will perform a physical examination to inspect your vagina, cervix, uterus, and ovaries.

Sometimes tests will be ordered like a pregnancy test, blood tests, a transvaginal ultrasound, a hysteroscopy, or an endometrial biopsy (when a tiny piece of tissue is removed from your uterus and examined under a microscope).

That said, here are some potential causes of AUB:

Structural Problems

Examples of anatomic problems that may be causing your abnormal menstrual bleeding include fibroids, polyps, endometriosis, endometrial hyperplasia, or certain cancers (for example, uterine cancer).

Hormone Imbalances

Various hormone abnormalities may lead to AUB, like thyroid, adrenal, or pituitary gland dysfunction. Polycystic ovarian syndrome is a fairly common cause and occurs when a woman's ovaries produce high amounts of male hormones (called androgens). 

Bleeding Disorders

Bleeding disorders like von Willebrand's disease or bone marrow conditions (for example, leukemia) are other possibilities.

Medications

Certain medications can affect uterine bleeding like steroids, chemotherapies, blood thinners, or certain herbal and spy products. Some birth control methods like intrauterine devices or birth control pills may cause abnormal bleeding. 

Infections

Sexually transmitted infections (for example, chlamydia or gonorrhea) can lead to inflammation of the uterus and abnormal bleeding. 

Whole Body Illnesses

Liver or kidney disease, anorexia, obesity, or rapid weight changes can lead to abnormal menstrual bleeding.

Understanding Polymenorrhea

After your doctor has performed a thorough examination and runs necessary tests, she may not find anything at all abnormal with your increased frequency of menstruation.

In other words, for some women, a shorter-than-average menstrual cycle is normal for them, and the precise "why" remains unclear. 

In this instance, treatment may not be necessary, although your doctor may want to monitor you for anemia, which is when your body can't produce enough hemoglobin to restock your blood cells after losing menstrual blood. Symptoms of anemia include pale skin, weakness, fatigue, lightheadedness, and shortness of breath.

If you are anemic from polymenorrhea or you are bothered by your frequent menstrual cycles, your doctor may recommend a combined hormonal contraceptive to lengthen the intervals between bleeding.

Another option is to use a contraceptive method that temporarily stops the menstrual flow or makes bleeding very light, such as MirenaDepo-Provera, or Nexplanon.

In addition to reducing your menstrual flow, your doctor may recommend a change of diet or iron supplements.

A Word From Verywell

In the end, it's important to see your doctor if you are experiencing a change in your menstrual cycle.

You may want to try tracking your period before your appointment, using either an app on your phone or a calendar. As well as marking the dates of your bleeding, it's helpful to note the severity of bleeding (light, medium, heavy).

Sources:

The American College of Obstetricians and Gynecologists. (2017). Committee Opinion: Management of Acute Abnormal Uterine Bleeding in Nonpregnant Reproductive-Aged Women. 

The American College of Obstetricians and Gynecologists. (2017). Frequently Asked Questions: Abnormal Uterine Bleeding. 

Bradley L. (2010). Cleveland Clinic: Menstrual Dysfunction. 

Kaunitz AM. (2017). Differential diagnosis of genital tract bleeding in women. Barbieri RL, ed. UpToDate. Waltham, MA: UpToDate Inc.