Understanding Heavy Periods


Heavy periods, also called menorrhagia or heavy menstrual bleeding (HMB), are defined as excessive or prolonged menstrual blood loss that interferes with assigned females at birth (AFAB)’s physical, social, emotional, and/or material quality of life. It is usually described as menstrual blood loss lasting longer than 7 days or severe menstrual bleeding with or without the presence of blood clots.1

Menorrhagia is one of the most common reasons that AFAB individuals are referred for specialist gynaecology care. In the UK, 1 in 20 people AFAB go to their GP each year because of heavy periods.1 In the US, more than 10 million AFAB each year are reported to have menorrhagia.2

Although menorrhagia is common, it can be difficult for AFAB to understand if they are experiencing heavy periods. If you suspect that your periods are heavier than they should be, this article will help to clarify any confusion you might have about your periods.

Menstrual cycle and menstruation

To understand what heavy periods are, we should first comprehend what a “typical” menstrual cycle is like. Menstrual cycles can be different from person to person, but generally, they follow a particular pattern that we can recognise.

Menstruation is also known as period. It is the time when an AFAB bleeds. A menstrual cycle is the time from the first day of AFAB’s period to the day just before the next period starts. This can be 23 to 35 days long, with an average of 28 days. 

Usually, periods last an average of 5 days, but there is a range of 2-7 days, which is considered normal. About 1-5 tablespoons of blood is lost during menstruation, but it is possible for people to have a greater volume of blood lost during their periods.3

The first period an AFAB has is called Menarche, and that is usually around 12 years of age, although there have been reports of people getting their first period as early as 8 years. Menopause, which is when the periods stop completely, occurs at about 45-55 years.4

The menstrual cycle is influenced by hormones. The fluctuation of those hormones creates the structure of a menstrual cycle. The major hormones influencing the menstrual cycle are the Follicle-Stimulating Hormone (FSH), Luteinizing Hormone (LH), Progesterone, and Oestrogen. 

The image below describes what happens during a cycle and how the previously mentioned hormones affect it.



In the first half of the menstrual cycle, the hormones FSH and LH are the dominant ones. They cause the ovaries to form eggs (which are called follicles). One of those follicles becomes dominant while the others die off. The dominant egg is released during ovulation, and FSH and LH are at their highest peak during this period. 

In the second half of the cycle, oestrogen and progesterone are the more dominant hormones, although oestrogen is strongly present in the first half of the cycle as well. Oestrogen and progesterone help to prepare the womb in case of a baby. They do this by thickening the lining of the womb. When the egg does not get fertilised, the womb lining sheds off, and that is what is called menstruation.

It is a very interesting process, yet a bit difficult to remember or understand. This NHS animation helps explain the process in a video format, making it easier to understand.

Identifying heavy periods

Since menstrual periods are different for everyone, it might be puzzling trying to identify what an abnormal period is. There are, however, ways to recognize a heavy period. The average blood loss during menstruation is 20 to 90 ml, but we can not exactly measure this to figure out whether we have lost more than 90 ml of blood. You may be losing more blood than normal if:

  • There are blood clots about 2.5cm in size (about the size of a 10 pence coin)
  • You need to change your pads or tampons every 2 hours or less.
  • You bleed through your clothes
  • You need to use 2 sanitary products together.
  • You bleed for more than 7 days.5

Other than these symptoms, if you notice that you feel tired easily or perhaps get breathless while having your normal chores done you may have lost a significant amount of blood during your periods.

Common causes of heavy periods

Sometimes, a heavy period is normal. This can happen with the first period, after a pregnancy, or just before menopause. Other times, however, it can be abnormal. In about half of people AFAB with menorrhagia, no known cause is found. Listed below are some of the causes, grouped into 3 major categories.2

Conditions related to the womb

Tumours or growths

Some tumours or growths, that are not cancerous, can cause heavy menstrual bleeding. They can be uterine fibroids or polyps.


A miscarriage or an ectopic pregnancy can cause menorrhagia. A miscarriage is when an unborn baby dies in the womb, while an ectopic pregnancy is when a baby is growing outside of the womb. This is usually not sustainable for the baby.


Endometriosis is another cause of menorrhagia. It is a condition in which the lining of the womb grows in other places, such as the ovaries and fallopian tubes, and is also one of the causes of menorrhagia. Usually, there are severe menstrual cramps, as well as heavy bleeding with this condition.

Birth control

Some types of birth control, for instance, intrauterine devices (IUDs), can cause HMB.


Cancers of the womb or cervix are implicated in the cause of menorrhagia.

Conditions related to hormones

Other illnesses or disorders

Bleeding-related disorders

Bleeding-related disorders, such as Von Willebrand disease, can cause heavy menstrual bleeding. Anticoagulant medications (medications that prevent or reduce blood clots), and some chemotherapy medications can also cause bleeding.

Nonbleeding-related causes

Nonbleeding-related causes are liver or kidney disorders, pelvic inflammatory disease, stress, and depression.

Complications and impact

One of the most common complications of heavy periods is anaemia (low healthy red blood cell levels). This can cause tiredness, dizziness, and fainting. Other complications related to the cause of the heavy periods, such as infertility, can be caused by endometriosis or fibroids.6

Menorrhagia is one of the most common reasons for referral to a gynaecologist (specialist in female reproductive medicine). More than one-third of adolescents in the UK suffer from heavy periods.1 Menorrhagia has a negative impact on the well-being of AFAB, preventing them from living their lives as they would like to. It can cause the need for multiple days off work or school, stop you from doing things that you love, and affect your social interactions in general. Some AFAB people feel embarrassed and alone when it comes to their symptoms, but there is no need to feel embarrassed as there is help available for you, should you require it.

Seeking medical evaluation

Sometimes, heavy periods do not need treatment. However, if you feel tired, weak, or you feel like your quality of life is being affected, please see your general practitioner (GP).

Your GP will ask you several questions ranging from symptoms about your period to your general medical history. Your doctor may also want to know about your family history and if there are any menstrual problems running in the family as well. This would help them know if there is a cause for the heavy periods and what the cause could be.

If your GP thinks there is no cause for your symptoms, they could offer some medications. 

Generally, a blood test is done to check if you have something called iron-deficiency anaemia, which can be treated with iron supplements. If they suspect a cause that needs further investigation, they will refer you to a specialist for some examinations and relevant tests. The examinations and tests done are dependent on the likely cause.5

Treatment options

There are many treatment options available, grouped into medical and surgical. These options can be used individually or in combination, depending on the severity of your symptoms.

Medical treatments

Medical treatments involve the use of hormonal and/or non-hormonal medications. Examples of hormonal medications used are combined oral contraceptive pills, levonorgestrel-releasing intrauterine system and oral progestogens. Some non-hormonal medications are tranexamic acid, anti-inflammatory pain medications, and iron supplements.1

The hormonal medications used are contraceptives. They are used because they help regulate menstrual periods by stopping ovulation and influencing the hormones involved in the menstrual cycle.

Tranexamic acid is a medication that helps to prevent a blood clot from breaking down after it has formed. This reduced the amount of blood loss during menstruation. 

Anti-inflammatory painkillers, such as naproxen and mefenamic acid, act by reducing the production of a particular chemical compound called prostaglandin. Prostaglandin has been implicated in HMB and menstrual cramps, so these medications help to alleviate HMB and menstrual cramps as well.

Surgical treatments

Surgical treatments are used when the cause can be treated with surgery. Some of them include uterine artery embolisation, endometrial ablation, and myomectomy. 

A uterine artery embolisation is a way to treat fibroids. Special substances are injected into blood vessels that carry blood to the womb causing the blood vessels to shrink. This reduces blood supply to the fibroids and that makes the fibroids shrivel up. 

A myomectomy procedure is when fibroids or polyps are removed from the womb. With endometrial ablation, the lining of the womb is surgically destroyed. This is usually done when the cause of HMB is a disorder in the womb lining or when an AFAB has had all the children they planned to have. 

Sometimes, the womb can be removed completely in a procedure known as a hysterectomy, but that is done only when necessary.

Coping with heavy periods

Having heavy periods can be distressing and exhausting. Even if you decide that you don’t need to see your GP, it is still exhausting having to plan for all kinds of circumstances each time you get your period. Although experiencing heavy periods affects your life, you can still manage this condition and have a good quality of life.

Coping with heavy periods would involve getting support; from family, friends, and healthcare professionals if needed. 

It is recommended to have a menstrual cycle diary to keep track of your periods so you won’t be caught off guard when your period comes. You can also use the menstrual diary to keep track of your symptoms so you can note if they are getting worse or better. 

AFAB people with HMB often have more severe menstrual cramps as well, so try to take analgesics and warm baths if you need to.


Heavy periods (Menorrhagia) are a very common condition affecting AFAB all over the world, especially between the ages of 15 and 49 years. Sometimes, it can feel isolating to manage this condition, but there are multiple treatments available. Do reach out to your family and/or a healthcare professional if you need it.  


Menorrhagia, or heavy menstrual bleeding (HMB), is a common concern for individuals assigned female at birth. This article offers insights into recognising and understanding HMB, emphasising the importance of awareness amidst varying menstrual cycles. The symptoms may significantly impact your well-being. If you experience HMB, managing it is achievable with diverse treatments available and a supportive community by your side; do seek help if needed.


  1. NICE [Internet]. [cited 2023 Nov 9]. CKS is only available in the UK. Available from: https://www.nice.org.uk/cks-uk-only
  2. CDC. Centers for Disease Control and Prevention. 2022 [cited 2023 Nov 9]. Heavy menstrual bleeding | cdc. Available from: https://www.cdc.gov/ncbddd/blooddisorders/women/menorrhagia.html#:~:text=If%20you%20need%20to%20change,It%20also%20can%20cause%20anemia.
  3. nhs.uk [Internet]. 2018 [cited 2023 Nov 9]. Periods and fertility in the menstrual cycle. Available from: https://www.nhs.uk/conditions/periods/fertility-in-the-menstrual-cycle/
  4. Menopause [Internet]. [cited 2023 Nov 9]. Available from: https://www.who.int/news-room/fact-sheets/detail/menopause
  5. nhs.uk [Internet]. 2017 [cited 2023 Nov 9]. Heavy periods. Available from: https://www.nhs.uk/conditions/heavy-periods/
  6. 6. Mount Sinai Health System [Internet]. [cited 2023 Nov 9]. Menstrual disorders information | mount sinai - new york. Available from: https://www.mountsinai.org/health-library/report/menstrual-disorders
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Olga Gabriel

Master's degree, Forensic Science, Uppsala University, Sweden

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