Prolonged Periods – Causes of Abnormally Long Menstrual Bleeding

Menstruation is a normal physiological process in the teen girls and women of reproductive age. However, it can vary among females. Not every woman will menstruate for the same duration. Even the quantity of menses (period blood) varies. However, there is an average duration of menstrual periods and average quantity of menstrual bleed that s considered within a normal range.

What is the Normal Duration of Periods?

The average menstrual cycle is of 28 days with menstruation lasting for 2 to 7 days. During this time the average blood loss is estimated to be 25 to 80 millilters (about 0.8 to 2.7 fluid ounces). If the periods are too long or too much blood is expelled then it is known as menorrhagia.

Both prolonged and heavy menstrual bleeding is not unusual. It may be a symptom of underlying problems like polycystic ovarian syndrome (PCOS), endometriosis or uterine fibroids. However, some women may experience unusually heavy or prolonged periods without any of these conditions.

How Long is Prolonged Periods?

As mentioned, the term menorrhagia refers to both prolonged and heavy periods. In terms of quantity, heavy periods means passing more than 80mL (2.7 fl oz). Prolonged periods refers to menstrual bleeding for more than 8 to 10 days. Therefore menorrhagia is also known as hypermenorrhea, which loosely translates to “too much menstruation”.

It is important to remember than prolonged or heavy periods should not be confused with other menstrual abnormalities, like irregular menstruation. A woman may experience prolonged or heavy periods but it is still regular, in that it occurs at the same interval with every cycle. Similarly, the menstrual blood may not have abnormalities like being too pale or dark or having excessive menstrual blood clots.

Other Types of Abnormal Periods

Menorrhagia should be differentiated from other similar conditions such as :

  • Metrorrhagia or intermenstrual bleeding is bleeding occurring any time in between periods or abnormal vaginal bleeding.
  • Menometrorrhagia or irregular periods is bleeding occurring at irregular intervals, with variations in the amount and duration. Conditions causing intermenstrual bleeding may ultimately lead to menometrorrhagia.
  • Polymenorrhea is too frequent menstruation, occurring within less than 21 days. This is also known as a very short menstrual cycle.

Causes of Prolonged Menstrual Bleeding

The most common causes of menorrhagia include :

  • Uterine fibroids, are abnormal non-cancerous (benign) growths in or on the uterus. From the different types of uterine fibroids, submucosal fibroids are more likely to cause menorrhagia.
  • Uterine polyps are abnormal elongated growths that protrude from the inner lining of the uterus. Most of these polyps are benign (non-cancerous).
  • Uterine cancer is another type of abnormal growth where cells of uterus become defective and grow rapidly. These growths are malignant (cancerous).
  • Endometrial hyperplasia is the excessive overgrowth of the cells of the endometrium. This is a benign condition but may lead to uterine cancer in some cases.
  • Pregnancy complications such as miscarriage.
  • Adenomyosis is the thickening of the uterus caused by the endometrium (uterine lining) growing into the outer muscular wall of the uterus.
  • Polycystic ovarian syndrome (PCOS) is where the male hormone levels are abnormally high in a woman’s body with cysts occurring in the ovaries. This causes various disruptions in menstruation and fertility.
  • Other hormonal imbalance may also lead to menorrhagia, for example as women approach menopause (perimenopause).
  • Dysfunctional uterine bleeding (DUB) is abnormal uterine bleeding without any definite pathology. There may be heavy and/or irregular bleeding. When all other causes of abnormal uterine bleeding have been excluded and vaginal examination does not reveal any pathology, a diagnosis of DUB is usually reached.
  • Endometriosis is where the inner lining of the uterus (endometrium) grows outside of the uterus.
  • Intrauterine device (IUD) for birth control can also cause menorrhagia.
  • Endocrine disorders such as thyroid or pituitary disorders.
  • Medication such as anticoagulants and pain relievers like aspirin. Hormone medication, including oral contraceptives, when not used as directed by the doctor.
  • Bleeding disorders such as von Willebrand’s disease.
  • Pelvic inflammatory disease (PID) is inflammation of the female reproductive organs which is usually due to an infection.

What are the dangers of menorrhagia?

Menorrhagia itself is usually not dangerous. It is rare where the blood loss is prolonged or excessive to the point that it can be life threatening. However, this is a possibility and if the bleed is sudden and severe then it should be treated as a medical emergency.

Instead the more common complications of heavy or prolonged periods is anemia. This means that the oxygen-carrying capacity of the blood is lower than normal. Another relatively common complication of menorrhagia is menstrual cramps associated with passing blood clots.

Diagnosis of Menorrhagia

The evaluation of any abnormal uterine bleeding, including menorrhagia, may be done by :

  • Clinical history. A thorough history will include the amount and duration of menstrual flow, the last menstrual period, age of menarche, and other associated symptoms. Pregnancy should be excluded.
  • Physical examination, including a pelvic examination, may detect a uterine fibroid, uterine polyp or other conditions.
  • Blood tests to investigate for anemia or other medical conditions such as thyroid abnormalities.
  • Pap smear
  • Endometrial biopsy
  • Ultrasound
  • Hysterosalpingography
  • Hysteroscopy
  • Sonohysteroscopy
  • Laparoscopy
  • Dilation and curettage (D&C) is considered the “gold standard” for diagnosis of abnormal uterine bleeding such as menorrhagia.

Treatment of Menorrhagia

Medical treatment is often effective and may be preferred in women who desire to have children.


The general principles of management include iron supplements for anemia and the use of NSAIDs such as ibuprofen both for pain relief as well as to reduce blood flow. Hormone treatment includes oral contraceptives such as estrogen and progesterone combined pill or progesterone alone. Use of a hormonal IUD which releases levonorgestrel may help control excessive bleeding. Treatment of underlying medical conditions causing menorrhagia is important.


  • Dilation and curettage (D&C)
  • Endometrial ablation where the first few millimeter thickness of endometrium is removed by means of various techniques such as laser or heat. Future pregnancies may be hampered following this method of treatment.
  • Endometrial resection is where an electrosurgical wire loop is used to remove the endometrium.
  • Surgical procedures depending upon the cause of menorrhagia such as myomectomy for uterine fibroid or polypectomy for uterine polyp removal.
  • Hysterectomy is a definitive treatment for menorrhagia but may not be favored by women who desire to have children.

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