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Irregular Period

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Last updated August 27, 2020

Irregular period questionnaire

Use our free symptom checker to find out what's causing your irregular period.

Understand irregular period symptoms, including 10 causes & common questions.

Irregular period questionnaire

Use our free symptom checker to find out what's causing your irregular period.

Irregular period symptom checker

Symptoms of irregular period

To get a bit technical, a woman's period, also known as menstruation or a menstrual cycle, is the shedding of blood and tissue from the uterine lining through the vagina in the absence of pregnancy. Menstruation usually occurs every 21 to 35 days; however, the definition of a "regular period" is different for every woman. An irregular period is any cycle that strays from your regular pattern.

Identifying irregular periods

In order to identify the features of your regular, normal period, take note of the following characteristics and patterns:

  • Duration: How long does your period usually last?
  • Quality of flow: How many times do you change your pad or tampon within a day? What type of sanitary protection do you use: Light? Medium? Heavy?
  • Pain: Is there pain associated with your cycle?
  • Other changes: Do you experience changes in mood or behavior during your cycle?

Common characteristics of irregular periods

For example, an irregular period may be associated with the following symptoms:

  • Bleeding that lasts longer than usual
  • Bleeding that is lighter or heavier than normal flow
  • Bleeding that occurs between expected periods: OR when you are not expecting a period.
  • Bleeding that occurs during a time in your life when it is not expected: Such as before puberty, during pregnancy or after menopause (which is defined as 12 or more consecutive months without a menstrual period).

Common accompanying symptoms of irregular periods

In addition to these changes, some people may also notice irregular period symptoms and signs such as:

The ability to recognize patterns of bleeding that fall outside of your regular period is very important. Seek medical care and follow up with your doctor if you experience irregular period symptoms.

Causes of irregular period

Since the causes of an irregular period are broad and varied, it is important to see your doctor to get the appropriate diagnosis.

Central causes

The menstrual cycle is controlled by a complex system of chemicals and messenger hormones that come from structures in the brain. These structures, the hypothalamus and pituitary gland, work in conjunction to stimulate the ovaries and regulate the menstrual cycle. Dysfunction in these central structures can result in irregular periods.

  • Intrinsic: Intrinsic causes, as in problems within the hypothalamus and pituitary themselves, will inevitably lead to irregular periods.
  • Extrinsic: Outside forces that can affect the hypothalamus and pituitary include things like cancerous and non-cancerous growths, poor blood flow and even diet. For example, women with very low body weight due to extreme exercise or conditions such as anorexia nervosa can have irregular periods due to damage to the hypothalamus.

Irregular period questionnaire

Use our free symptom checker to find out what's causing your irregular period.

Irregular period symptom checker

Reproductive causes

The brain may control the menstrual cycle, but without the reproductive organs there would be nothing to act upon. Normal processes such as pregnancy and menopause can affect the regularity of periods but there are many abnormal processes that occur reproductively that also affect the menstrual cycle.

  • Pregnancy: A missed or notable irregularity in your period is often the first sign of pregnancy. The menstrual cycle happens in the absence of pregnancy, so when pregnancy occurs there is no need for this process.
  • Age-related: Irregularity in periods is very common in both the early stages of puberty and the final stages of a woman's reproductive years (menopause).
  • Obstructive: Cancerous and noncancerous growths within or on the uterus, cervix and ovaries can cause irregular periods. These growths can disrupt the normal flow and shedding of the uterine lining causing heavier periods, missed periods or periods that occur when not expected.
  • Hormonal: Normally, the brain produces and delivers hormones that trigger the production of hormones in the ovaries necessary for a normal menstrual cycle. Often for reasons unknown, a hormonal imbalance can occur within the reproductive tract leading to irregular periods.

Bleeding disorders

Bleeding disorders can result in irregular periods.

  • Functional: Medical conditions such as von Willebrand disease (clotting disorder) that affect the way different components of your blood function can result in irregular periods.
  • Synthetic: Your liver, and to a lesser extent, your kidneys, are organs that are important in making the components of your blood that regulate bleeding. If there is a malfunction in these organs such as liver disease or kidney disease, you may experience irregular periods as well.


Medications can result in irregular periods.

  • Contraceptives: Contraceptives are medications used to control and prevent pregnancy; as such, they directly affect the menstrual cycle and can change the duration and quality of your period as a side effect.
  • Anticoagulant: Medications used to thin the blood for other medical conditions such as heart disease or clotting disorders can cause bleeding not related to a cycle, making it seem like you are having an irregular period.

This list does not constitute medical advice and may not accurately represent what you have.

Polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a hormonal condition very common in women of reproductive age, resulting in menstrual abnormalities as well as an excess of the androgen testosterone. PCOS can affect a woman's overall health and appearance and often has a si..

Overactive thyroid

The thyroid is a small, bow-tie shaped gland in your neck. Its main job is to produce thyroid hormone (known as T3 or T4), which serves a wide array of functions throughout the body.

When too much thyroid hormone is released, the body’s metabolism gets ramped up, causing symptoms ...


Hypothyroidism, or "underactive thyroid," means that the thyroid gland in the neck does not produce enough of its hormones. This causes a slowing of the body's metabolism.

The condition can occur due to autoimmune disease; any surgery or radiation treatment to the thyroid gland; some medications; pregnancy; or consuming too much or too little iodine. It is often found among older women with a family history of the disease.

Common symptoms include fatigue, constantly feeling cold, weight gain, slow heart rate, and depression. If left untreated, these and other symptoms can worsen until they lead to very low blood pressure and body temperature, and even coma.

Diagnosis is made through a simple blood test.

Hypothyroidism is easily managed with daily oral medication. The patient usually starts feeling better after a couple of weeks and may even lose some extra weight. It's important for the patient to be monitored by a doctor and have routine blood testing so that the medication can be kept at the correct levels.

Rarity: Rare

Top Symptoms: fatigue, depressed mood, difficulty concentrating, weight gain, muscle aches

Urgency: Primary care doctor

Symptoms of menopause

Menopause is the name for the natural process by which the menstrual cycle (period) stops happening in a woman. Usually, the process is gradual (takes months or years) and occurs from the age of 45 to 55 years. Menopause is officially diagnosed once a woman stops having a period for 12 months continuously. A woman with menopause will notice a decrease in the number and regularity of her periods until they completely stop. In addition, she may notice a number of symptoms that occur as a result of decreased estrogen levels, such as hot flashes, changes in mood, sleep problems, vaginal dryness, changes in libido, and changes in sexual function. Certain medications exist that can decrease these symptoms.

Rarity: Common

Top Symptoms: fatigue, delay in or irregular periods, vaginal discharge, anxiety, trouble sleeping

Symptoms that always occur with symptoms of menopause: delay in or irregular periods

Urgency: Self-treatment

Premature ovarian failure

"Premature ovarian failure" (POF), also called "primary ovarian insufficiency" and "early menopause" happens when the ovaries stop working well too early in life. Naturally menopause occurs between the ages 45 and 55. Symptoms of menopause are changes in menstrual period, missing periods, hot flashes, mood changes and vaginal dryness.

Rarity: Common

Top Symptoms: fatigue, anxiety, irritability, vaginal itch or burning, muscle aches

Urgency: Primary care doctor

High prolactin hormone level

Hyperprolactinemia is a common hormonal disorder in which there are higher than normal levels of prolactin in the blood.

Rarity: Rare

Top Symptoms: headache, vaginal bleeding, irregular period, decreased sex drive, enlargement of breasts

Urgency: Primary care doctor

Cushing syndrome

Cushing Syndrome is a hormonal disorder. The cause is long-term exposure to too much cortisol, a hormone that the adrenal gland makes. Sometimes, taking synthetic hormone medicine like corticosteroids to treat an inflammatory disease leads to Cushing's syndrome.

Rarity: Rare

Top Symptoms: fatigue, headache, depressed mood, weight gain, back pain

Urgency: Primary care doctor

Acute stress disorder

Irregular period questionnaire

Use our free symptom checker to find out what's causing your irregular period.

Irregular period symptom checker

Acute stress disorder (ASD) is a psychological condition caused by trauma, especially by any violent attack such as robbery, assault, or combat. "Acute" means that clear symptoms appear within days of the traumatic event. Most susceptible are those with a previous history o...


Bulimia is an eating disorder characterized by recurrent episodes of binge eating followed by compensatory behavior, such as self-induced vomiting, fasting, excessive exercise, or abuse of laxatives or diuretics.

Despite typically having a normal weight, people with bulimia are often persistently concerned with th...


Anorexia nervosa is a type of eating disorder. Anorexia usually affects adolescents or adults. While weight loss is the primary feature of anorexia, this condition can affect many organ systems throughout the body.

Irregular period treatments and relief

Seek prompt medical attention when you notice symptoms of an irregular period. Depending on the cause of your symptoms and the results of any testing, your doctor may begin one or more of the following irregular period treatments.


Medications may be recommended by your medical provider such as the following.

  • Hormones: Many central and reproductive causes of irregular periods are the result of an imbalance of hormones in the body. Your doctor may prescribe treatment in the form of these hormones in order to restore your body's balance.
  • Changes to your current regimen: If contraceptive methods or other medications are contributing to your irregular period symptoms, your doctor may discuss stopping your current medications in favor of a new regimen.
  • Other treatment: If your irregular period symptoms are caused by an underlying bleeding disorder or systemic disease, your doctor will treat the primary disease first and monitor its effects on your menstrual cycles.


When medications fail, some causes of irregular periods can be treated with surgical options that either remove masses or decrease the lining of the uterus. Most cancers of the reproductive organs are removed by surgery.

Pregnancy care

If your irregular period is caused by pregnancy your doctor will discuss available options for care.

Questions your doctor may ask about irregular period

  • When was your last menstrual period?
  • Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • Have you had any changes in your weight?
  • Are you sexually active?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

Share your story
Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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  1. Gray SH. Menstrual Disorders. AAP News & Journals Gateway. 2013;34(1):online. AAP Link
  2. Abnormal Uterine Bleeding. ColumbiaDoctors. ColumbiaDoctors
  3. Hyperprolactinemia (Prolaction Disorder). ColumbiaDoctors. ColumbiaDoctors Link
  4. Reed BG, Carr BR. The Normal Menstrual Cycle and the Control of Ovulation. In: De Groot LJ, Chrousos G, Dungan K, et al., eds. Endotext. South Dartmouth, MA:, Inc.; 2000. NCBI Link
  5. Wisse B. Hypothalamic Dysfunction. U.S. National Library of Medicine: MedlinePlus. Updated May 7, 2017. MedlinePlus Link
  6. Torborg L. Mayo Clinic Q and A: Menstrual Irregularities Not Uncommon in Decade Prior to Menopause. Mayo Clinic. Published January 12, 2016. Mayo Clinic Link
  7. Finke A, Haldeman-Englert C. Prothrombin Time. University of Rochester Medical Center. URMC Link