8 Causes of Heavy Periods

Oct 6, 2021 | Hormone Balance, Menstrual Cycle, PMS, Root Causes, Symptoms

Most of us have experienced the complications of the occasional overly heavy flow day. You know the routine. Tie a sweater around your hips like it’s the ‘90s, rinse your undies in cold water before throwing them in the wash, double up with your menstrual products, curl up on the couch, and loathe Mother Nature for giving you this “gift.”

But if you’re experiencing a particularly heavy period month after month, you have what’s medically termed “menorrhagia.” This extreme menstrual bleeding is defined by abnormally heavy or prolonged periods.

For many women, heavy bleeding and cramps are their “normal” periods. So how do you know if your periods are normal or whether you have menorrhagia?

How Heavy is Too Heavy?

A heavy day or two is expected during your period, but what constitutes “too heavy”? For most women, losing up to 2 or 3 tablespoons (30 to 50 milliliters) a month is normal, and anything over 5 tablespoons (80 milliliters) is considered menorrhagia.

But how do you really know how much you’re losing? You can base it on how often you change your menstrual products.

Menstrual cups are convenient because they often have measuring marks on them. Even if they don’t, their packaging will provide the cup’s measurements so you can keep track of how much blood you lose throughout your period.

As for pads and tampons, the regular sizes hold about 5 milliliters of blood, while the super absorbent ones hold around 10 milliliters.

Interestingly, only about 36% of the fluid you lose is menstrual blood, and the rest is cervical mucus and uterine tissue.

So to calculate accurately how much blood you lose during your period, multiply the number of hygiene products you use by how much liquid they hold. To find out how much of that is blood, multiply that number by 0.36.

For example, if you use 10 super-absorbent pads (10 milliliters), then 10 X 10 = 100. Multiply 100 by 0.36 (the percentage that’s actually blood), which equals 36 milliliters of blood loss. That would be well within the healthy range.

But what if, after a few months of tracking your monthly blood loss, you find you’re losing more than 80 milliliters (or 5 tablespoons) of blood on average? Then you need to investigate further to understand why this is happening.

Keep in mind that super heavy periods are NOT normal – they are a sign from the body that there’s something going on.

What are the Risks of Heavy Periods?

Your period is your monthly report card. Suppose you notice that your period is heavier than usual, or you experience heavy periods with blood clots. In that case, it could mean that you have a hormonal imbalance or another more serious condition.

Heavy bleeding can even be a sign of certain cancers or a miscarriage, so it’s essential to track what is normal for you and get tested when something’s not.

If you have consistent heavy periods, it could lead to anemia or a low red blood cell count that will leave you feeling weak and exhausted. Prolonged heavy periods also make daily activities uncomfortable and stressful.

So it’s vital to pinpoint the root cause of your heavy period so it can be treated and you can continue living your life to its fullest.

If you’re not sure why you have heavy periods, here 8 of the most common causes.

8 Causes of Heavy Periods



Up to 80% of women have experienced fibroids. But just because it’s common, it doesn’t mean it’s normal. Fibroids are growths or benign tumors that form in the muscle of the uterus. They can be microscopic or as large as a grapefruit.

As they grow and press against the endometrial tissue, they can cause excess and prolonged bleeding. Your uterus contracts the blood vessels to stop bleeding. Unfortunately, fibroids interfere with this process causing periods to last longer.

Fibroids also produce proteins that stimulate the blood vessels in the uterus to bleed more.


Polyps are different from fibroids in that they grow from endometrial tissue rather than from muscle tissue. They occur when cells overgrow and aren’t sloughed off during menstruation.

Polyps irritate and expose blood vessels in the surrounding tissue causing unpredictable and heavy bleeding.

Copper IUD

Heavy bleeding is a common side effect of the copper, non-hormonal IUD. For many women, periods get better after about six months, but not always. Mine never got better until after I had it removed.

Because of the likelihood of increased bleeding with a copper IUD, it’s not recommended for women who already experience heavy periods.

You can read more about my experience with the copper IUD here.

Estrogen Dominance

Progesterone slows down the thickening of your uterus lining or endometrium before your period starts. When your estrogen to progesterone ratio is off, meaning that you have more estrogen than progesterone, the lining in your uterus becomes overly thick.

Once lining sheds during your period, you’ll experience a heavier flow that’s often accompanied by large blood clots.

Polycystic Ovarian Syndrome

Women with Polycystic Ovarian Syndrome (PCOS) can experience heavy periods and blood clots. Because periods are infrequent, endometrium builds up month after month. When you finally get your period, it is much heavier and longer because of the extra thick uterine lining.

Because PCOS can cause heavier periods, it also makes it harder for the body’s anticoagulants to keep up, and they can’t prevent the blood from clotting in time. So not only can periods be heavier, but you might see more blood clots.


When you don’t have enough thyroid hormone, chances are you’re deficient in progesterone as well, and remember, progesterone is key to reducing a heavy flow.

Low thyroid function can also mean you’re not producing enough coagulation factors to slow bleeding down during your period.

Additionally, when you’re not making sufficient thyroid hormone, you are exposed to more estrogen. That’s because you can’t make as much estrogen-binding protein (SHBG) and more estrogen leads to a heavier flow.


Endometriosis is a condition diagnosed by tissue similar to your endometrium growing outside of the uterus. It can cause more painful periods, excessive menstrual bleeding, and shorter cycles. Since women with endometriosis generally have thicker uterine tissue, bleeding also tends to last longer overall.


Statistics show that up to 65% of women suffer from adenomyosis. It’s similar to endometriosis in that the same cells in the uterus grow where they don’t belong.

The difference is that while women with endometriosis experience uterine tissue growth outside the uterus, adenomyosis is the growth of these cells deep into the muscular wall of the uterus.

The uterus can thicken to double or triple its size over the course of a month, leading to very heavy bleeding during your period.

Treatment for Heavy Periods

Heavy periods can be treated and should never be written off as “normal” or “untreatable.” Conventionally, doctors prescribe NSAIDs, birth control pills, or surgical procedures to treat heavy periods. However, these each come with other side effects.

Some women prefer to use more natural herbs and remedies to help with their heavy periods, but these will only help if you understand the cause of your heavy periods. Some herbs can even make periods worse if taken for the wrong conditions.

The best place to start before taking any medications or supplements is with functional testing. It will give you an overview of what’s going on in your body and what’s most likely causing your heavy flow. Only then can you make appropriate lifestyle and diet changes and begin incorporating herbs or other therapies.

If you’re interested in getting to the root cause of your heavy periods, contact me about how functional testing can help.


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