What Does a Heavy Period Flow Mean? {Must Read}

Last updated 01.29.2024 | by Dr. Karen Pike | 8 Minutes Read

This article has been reviewed and fact checked by Dr. Karen Pike, a senior physician administrator and board-certified emergency room doctor actively working in northern California. Read more at our medical disclaimer page.

More than 10% of women suffer from menorrhagia, the technical term for heavy menstrual bleeding. This common condition can affect us at any time of life, but it’s particularly common during perimenopause- the build-up to menopause. Hormonal shifts that happen during this phase of life can play havoc with our menstrual cycles, causing irregular menstrual bleeding and an increase in menstrual flow.

However, several other potential factors may be causing heavy bleeding during your period, and excess blood loss can lead to health complications such as anemia. So, it’s important to identify the underlying cause of your symptoms as soon as possible.

Throughout the later stages of my own perimenopause, I noticed that my periods were becoming heavier. This was unusual to me, as I had always experienced a relatively light flow in the past. That being said, I wasn’t too concerned. I knew that heavy or prolonged periods were common during perimenopause, and with menopause approaching, it wouldn’t be long until periods were a thing of the past.

But unbeknownst to me, this repeated increase in blood loss every month was taking its toll on my body. I began to feel tired and drained, and I was struggling to get through my busy work days in the emergency room.

Eventually, I booked an appointment with my doctor. She ordered some routine blood tests, and to my surprise, the results showed that I was on a fast track to iron deficiency anemia. My heavy periods had reduced the number of red blood cells in my body, and in turn, my iron levels were rapidly falling.

Thankfully, with some small changes to my diet and some extra iron supplementation, it wasn’t long before I was feeling much better. However, this certainly served as a wake-up call to pay more attention to my body and monitor any changes as they occur.

So, have you noticed that your period has become heavier recently? Are you wondering why? This post is for you. Below, I’ll explain the symptoms of a heavy period flow and discuss the potential reasons why it happens.

What are The Symptoms of Heavy Menstrual Bleeding?

Many women think they have a heavy menstrual flow (also called menorrhagia). However, their level of blood loss is actually normal.

But this isn’t the case for everyone. Around 10% of women really do experience excess blood loss during their menstrual periods. Yet it’s very difficult, if not impossible, to accurately measure the amount of blood that leaves the body during a period. And so the only way to know for sure if your periods are heavy is to talk with your doctor.

That being said, several signs and symptoms can indicate abnormal uterine bleeding, including:

  • Needing to change your pad or tampon every hour, multiple hours in a row
  • Needing to wear a tampon and a pad, or two pads, to control blood flow
  • Needing to get up during the night to change your tampon or pad
  • A period that lasts longer than seven days
  • Passing large blood clots bigger than the size of a quarter (1 inch) in diameter

When to See a Doctor

If you experience any of the symptoms above, you may find that your daily activities are restricted during your period. Some women even need to take time off work.

You might also feel tired or weak due to losing more red blood cells than your body can produce. This is because menstrual bleeding can cause anemia. I experienced these same symptoms myself, and despite my medical background, I didn’t realize that my weakness and fatigue were due to an iron deficiency caused by blood loss during my period.

So, if you think your periods are heavy, it’s important to visit your doctor as soon as possible. They can perform a simple blood test to measure your iron levels. If necessary, they will prescribe supplements to help replenish your iron stores.

What are the Causes of a Heavy Period Flow?

There are multiple potential causes of a heavy period, including perimenopause.

Perimenopause and Heavy Menstrual Bleeding

Our menstrual cycles are driven by our hormones. So, during perimenopause, shifts in the levels of estrogen and progesterone can increase the natural flow of your period. These hormonal changes can also lead to irregular periods, too.

If you’re going through perimenopause and you’re experiencing heavy menstrual bleeding, there’s a good chance that natural hormonal shifts in your body are to blame.

However, multiple underlying medical conditions can cause the same symptoms.

Other Causes of Heavy or Prolonged Bleeding

Other Causes of Heavy or Prolonged Bleeding

There may be other causes of prolonged causes of prolonged bleeding, some of which are discussed below:

1. A new intrauterine device (IUD)

IUDs are one of the most effective forms of birth control. However, they can cause an increase in menstrual flow in some women. This is particularly common within the first few months of implantation, and eventually, these symptoms should settle down.

Copper IUDs are more likely to cause this type of bleeding. Conversely, hormonal IUDs are more likely to reduce menstrual blood loss and menstrual cramps.

2. Certain medications

Hormonal medication such as birth control pills can interfere with the body’s natural balance of estrogen and progesterone. While usually, the synthetic versions of these hormones found in birth control pills reduce menstrual bleeding, in some circumstances, they can lead to a heavier flow.

Anticoagulants and blood thinners, such as aspirin, warfarin, and enoxaparin, can also cause heavy menstrual bleeding.

3. Pregnancy complications

A sudden heavy period during pregnancy can indicate a serious issue, such as miscarriage or ectopic pregnancy. Ectopic pregnancy is where the fetus develops outside of the uterus. If left untreated, it can cause life-threatening complications.

4. Hormone imbalance

Hormone imbalances can happen at any stage of life. Excess levels of estrogen can cause the lining of your uterus to thicken. Typically, this will result in heavy menstrual bleeding, often accompanied by cramping during your period.

5. Bleeding disorders

As many as a third of women who suffer from menorrhagia also have a bleeding disorder. Bleeding disorders are medical conditions that affect the blood’s ability to clot. One such disorder is Von Willebrand disease, which is more prevalent in women than it is in men.

6. Uterine disorders

Many women with heavy menstrual bleeding also have an underlying uterine condition. The most common of these conditions are:

  • Uterine Polyps: characterized by small benign growths that form on the part of the lining of the uterus. The bigger these growths become, the heavier your periods will be.
  • Uterine Fibroids: It’s estimated that around 70% of women will develop uterine fibroids at some stage in their life. These benign growths occur on the outside of the uterus, and they typically go unnoticed. However, for some women, they can cause debilitating pain and heavy bleeding during periods.
  • Adenomyosis: Adenomyosis is a chronic condition caused by an excess of endometrial-type tissue within the uterine muscle. As these tissues continue to grow, they can cause pelvic pain and heavy periods.
  • Endometriosis: Endometriosis is characterized by endometrial-type tissue growths on the outside of the uterus. This tissue can develop throughout the pelvic region, including on the bladder and bowel. Like adenomyosis, endometriosis can cause pelvic pain and heavy periods.

7. Polycystic Ovary Syndrome (PCOS)

PCOS is the most common endocrine condition in reproductive-aged women. The disorder is characterized by the formation of multiple cysts on the surface of the ovaries, affecting ovulation and, in some cases, leading to infertility.

Women with PCOS often have irregular periods, spotting or bleeding between periods, and a heavy period flow.

8. Cancer

In rare cases, heavy bleeding during menstruation can be a sign of certain types of cancer, including uterine, cervical, and ovarian cancer. However, usually, women notice other symptoms before experiencing heavier periods.


Can perimenopause also cause irregular periods?

Yes, alongside unusually heavy periods, perimenopause can also make your periods irregular. This is due to shifts in the body’s levels of estrogen and progesterone.

Are there any health complications associated with heavy periods?

Yes. Menorrhagia (heavy menstrual bleeding) can lead to anemia. Anemia is a potentially serious condition caused by a lack of iron in the blood. It can leave you feeling tired and lead to other health complications. So, if you or someone you know shows signs of anemia, it’s important to talk to your doctor right away.

Are there any treatment options for heavy menstrual periods?

Yes. There are various treatments that can help to reduce bleeding during your period. In the case of hormone-driven disorders, hormonal medications such as birth control or hormone replacement therapy (HRT) may help to make periods more regular and reduce blood loss during menstruation.
If uterine polyps, endometriosis, or adenomyosis are to blame, your doctor may recommend a procedure called endometrial ablation or resection.


Heavy periods can happen to all women of reproductive age. However, the symptom is particularly common during perimenopause.

I learned the hard way that losing too much blood during your period can lead to complications such as anemia. So, if you are suffering from heavy periods, it’s important to monitor your overall health and talk to your doctor if you have any concerns. Your healthcare provider will ask you about your medical history, conduct any necessary tests, and provide an accurate diagnosis. Then, they can offer a treatment plan that can help.


  • Dr. Karen Pike

    Dr. Pike is a senior physician administrator and board-certified emergency room doctor actively working in northern California. She received her undergraduate degree at Dartmouth College, where she graduated Phi Beta Kappa and played collegiate soccer. She attended Georgetown University for medical school and performed her residency in emergency medicine at Stanford University. She was part of the first-ever, women-majority emergency medicine program in United States. Dr. Pike is also the primary medical consultant for “Grey’s Anatomy,” a role she has held since the pilot episode when she partnered with Shonda Rhimes as the show’s original medical consultant. At her hospital, she was the second woman Chief of Staff. Today serves as the Director of the Emergency Department. Whether in leadership or direct patient care, her dedication to excellence in communication, quality, and collaboration is unwavering.