Why Is My Period So Heavy?

The week of your period is hard enough — you have to deal with cramps, moodiness, and carrying around a supply of pads or tampons. But what if your menstrual bleeding is so heavy that you can’t even “do” normal life?

Whether it’s a new issue or one you’ve been dealing with for years, heavy periods may be a sign of another medical problem. And heavy menstrual bleeding, also called menorrhagia, can cause other health issues. 

If you have to think twice about leaving the house because you’re going through pads or tampons so quickly, there’s a good chance heavy menstrual bleeding is affecting you.

How much is too much menstrual bleeding?

Let’s start with what is considered normal menstrual bleeding. If you have average periods, you’ll change your pad or tampon about every 3 to 4 hours and bleed for 4 to 5 days. Within that time, some days will be a little heavier, some a little lighter, and you will lose about 2 to 3 tablespoons of blood.

But menstrual bleeding is different for each person, and it naturally changes over your lifetime. So, if your period is heavier than the average — or heavier than it used to be — how do you know if you have a problem?

Researchers have developed tools to estimate blood loss by how often pads or tampons are changed, how saturated they are, and how many days a period lasts.

Heavy menstrual bleeding is the loss of more than 5 tablespoons of blood during your period. Besides estimating your blood loss, consider the following questions to see if you may have heavy periods:

• Does your period last for more than 7 days? 

• Do you have to change your pad or tampon every 1 to 2 hours?

• Are your pads and tampons saturated with blood? 

• Do you notice blood clots (gel-like clumps of blood)?

• Do you feel like you don’t have enough energy to get through your day, even after your menstrual cycle?

• Are you pale?

• Do you get short of breath easily?

If you answered yes to any of the above, you may be dealing with heavy menstrual bleeding.

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5 reasons your period may be heavy

If your periods are heavy, the next question is, why? Finding the answer may take some exploration. There are lots of causes for heavy menstrual bleeding, but most fall into one of five categories:

1) Problems with the uterus 

Did you know that menstrual blood comes from the lining of your uterus? Each month, the tissue on the inside of the uterus builds up in preparation for pregnancy. But if an egg isn’t fertilized, that lining sheds, which you experience as your period.

Knowing this, it’s easy to see how problems with the uterus can cause heavy menstrual bleeding. Some include:

• Polyps or fibroids: These benign (noncancerous) growths within the uterus can prevent effective contraction of the uterus (what you feel as cramps), which can result in heavy bleeding.

• Endometrial problems: If the endometrium (lining of the uterus) is inflamed or infected, the normal process of monthly shedding may not work as well and could lead to heavy menstrual bleeding. 

• Cancer or precancer of the uterus or cervix: If abnormal tissue is growing in the uterus or cervix, it can bleed easily due to rapid growth.

• Complications of pregnancy: Miscarriage (losing a pregnancy) or ectopic pregnancy (a pregnancy that implants outside of the uterus, like in the fallopian tube) can cause heavy bleeding. And this can happen even before someone knows they're pregnant. 

2) Hormonal imbalances 

Hormones in your brain interact with hormones in your ovaries to control menstrual cycles. Heavy periods can happen when this system is out of balance. In the healthcare world, it’s called “ovulatory dysfunction.” Your normal hormones can be changed by:

• Polycystic ovary syndrome (PCOS): PCOS is a common hormone imbalance that is associated with cysts on the ovaries and irregular, sometimes heavy, menstrual cycles.

• Thyroid problems: If your thyroid isn’t functioning properly — like with hypothyroidism, where you can't make enough thyroid hormones — menstrual cycles may be affected and become heavier, lighter, or more irregular.

• Hyperprolactinemia: Prolactin is a hormone that comes from the brain and helps to control your menstrual cycles. If you have too much of this hormone, you might have heavy periods or stop having periods altogether.

• Stress: Mental or physical stress can affect hormone levels, including prolactin, and it may change menstrual bleeding. 

• Having overweight or obesity: Hormones made in adipose tissue (fat) can affect the uterus and lead to heavy periods.

3) Bleeding disorders 

If you tend to bleed easily, you’ll likely have heavier periods. Some bleeding disorders run in families. For example, Von Willebrand disease is the most common hereditary (meaning it can be passed on in families) bleeding disorder in the U.S. Other bleeding problems come out of the blue, or they result from another health condition like liver disease. And as we’ll see next, some medications can also cause you to bleed.

4) Medications

Sometimes, medications you take for other health problems can cause heavy menstrual bleeding as a side effect.

Prescription blood thinners like Warfarin, Lovenox (enoxaparin), and Xarelto (rivaroxaban) increase your risk for bleeding heavily with your periods. Some over-the-counter medications like aspirin and ibuprofen (Advil, Motrin) also have a blood-thinning effect.

Besides blood thinners, any medication that affects your hormonal balance may cause heavy periods. Some examples include hormones that contain estrogen, progesterone, or testosterone — or other medications like amitriptyline, nortriptyline, and Phenergan.

5) Medical treatments

Certain medical treatments can also cause heavy menstrual bleeding. Some people experience heavier periods after having tubal ligation surgery (“tubes tied”), especially if they have had a C-section (a surgical procedure where a baby is delivered through the abdomen). And people who use the copper intrauterine device (IUD) for birth control commonly see an increase in their menstrual blood loss. 

Getting help for heavy periods

If you’ve read down this far and have any suspicion that your period is heavy, it's best to check in with your healthcare provider. Finding the specific cause of your heavy menstrual bleeding is important to get you feeling better, and to prevent other problems like anemia.

Here are a few things to look out for that will need more urgent medical attention: 

• You’re experiencing heavy bleeding, especially with symptoms of shortness of breath or dizziness.

• You soak through pads or tampons in 1 to 2 hours or less.

• You have blood clots larger than a quarter.

• Your heavy period lasts more than 7 days.

Can heavy period bleeding lead to other health conditions?

Bleeding from heavy periods can cause iron-deficiency anemia. Anemia means your body doesn’t have enough red blood cells, which carry oxygen to your tissues. And iron is an essential component for your body to make red blood cells. So, blood loss from heavy periods may result in a double whammy: low red blood cells and not enough iron to make more.

Without enough iron or red blood cells, you may feel tired or short of breath. Or you may have trouble with athletic performance. If your anemia is severe, you could be at risk for damage to your vital organs, like having a heart attack or a stroke. Your healthcare provider may recommend that you take an iron supplement to prevent these issues from happening.

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Written by:

Shane McCarthy, DO

Shane McCarthy, DO, practices full-spectrum family medicine and is board certified through the American Board of Family Medicine. She has over 20 years of experience.

Edited by:

Aunna Pourang, MD

Aunna Pourang, MD, graduated from the University of Florida College of Medicine’s Medical Honors Program and is board-certified in family medicine (Mayo Clinic). She is also fellowship-trained in integrative medicine (Academy of Integrative Health and Medicine).

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