Fibrinogen is an essential clotting factor that helps your body heal from injuries. Low levels can cause excessive bleeding and pregnancy complications. Keep reading to understand what can cause your levels to drop too low and what you can do to increase them.

Causes of Low Fibrinogen Levels

According to the World Federation of Hemophilia, low fibrinogen blood levels account for about 7% of bleeding disorders worldwide, which are more common in women than men [1].

1) Trauma

Acquired hypofibrinogenemia, defined as fibrinogen deficiency developed later in life, is most often caused by excessive blood loss. This is because most of the body’s fibrinogen has been used up to stop the bleeding [2].

Excessive blood loss lowers fibrinogen levels.

2) Medication

Medication used to reduce blood clots, such as streptokinase, urokinase, and tissue plasminogen activators have reduced blood levels of fibrinogen in the lab and human studies [3, 4, 5].

Urokinase is a trombolitic (“clot-busting“) drug that decreased blood fibrinogen levels by an average of 35% in a study of 204 patients with stroke after 24 hours [4].

According to an analysis of 11 studies, the anti-seizure (epileptic) drugs valproic acid and phenobarbital also reduce blood fibrinogen [6, 7].

In humans, multiple studies have found that some types of chemotherapy can reduce blood fibrinogen levels, likely by inhibiting liver protein production [8, 9, 10].

A 2-week regime of anabolic steroids reduced blood fibrinogen levels by 22% in a clinical trial of 14 healthy adults [11].

The muscle pain reliever pentoxifylline lowered blood fibrinogen levels in a study of 427 patients with peripheral vascular disease, likely by inhibiting its production [12, 13].

People with low fibrinogen are recommended to avoid aspirin or other blood thinners that will further decrease their ability to form blood clots unless prescribed by a doctor [14].

On the other hand, doctors often recommend anticoagulant drugs (such as heparin, aspirin, or Lepirudin) as an add-on to fibrinogen replacement therapy to help reduce the likelihood of an internal blood clot [15].

Anabolic steroids and certain drugs used to treat excessive clotting, seizures, cancer, and muscle pain can lower fibrinogen. If your fibrinogen is low, avoid aspirin and other blood thinners without a prescription.

3) Illness

Liver disease can cause low fibrinogen levels by either impairing the body’s ability to produce fibrinogen or over-stimulating the breakdown of clots and consumption of fibrinogen [16, 17, 18].

Blunt trauma to the liver specifically impaired fibrinogen production in pigs, leading to a decline in fibrinogen levels [19].

Leukemia may reduce fibrinogen levels by promoting clot formation and fibrinogen degradation (surveys of 1,304 patients, 17 patients, and 379 patients). As a result, hypofibrinogenemia (fibrinogen deficiency) may serve as an early marker for leukemia diagnosis [20, 21, 22].

Both liver disease and leukemia can impair the way fibrinogen is used or produced in the body, lowering its blood levels.

4) Genetic Disease

Congenital Hypofibrinogenemia

Congenital hypofibrinogenemia is characterized by low blood levels of fibrinogen (between 0.5 and 1.5 g/L) with prolonged clotting times [23].

Caused by either a dominant or recessive mutation, this condition is estimated to affect as many as one in 100 people. Many of these people present no symptoms, maintaining enough fibrinogen to clot minor injuries (survey of 100 patients; genomic database analysis including approximately 140,000 people) [24, 25, 26, 27].

Congenital Afibrinogenemia

Congenital afibrinogenemia is characterized by extremely low blood levels of fibrinogen, (less than 0.1 g/L). Clotting time is unable to be determined because the blood never clots [28].

It is a recessive disease, meaning that both parents must have the genetic mutation for their child to acquire the disorder, which affects approximately 10 people per million in the general population. Afflicted individuals are typically diagnosed as infants (survey of 155 participants; genomic database analysis including approximately 140,000 people) [23, 29, 25].

People born with congenital hypofibrinogenemia or congenital afibrinogenemia have low fibrinogen levels.

Congenital Hypodysfibrinogenemia

Congenital hypodysfibrinogenemia includes low levels of fibrinogen as well as structural abnormalities in the molecule that do not allow it to properly create clots [23, 30].

It is autosomally dominant, and likely more common than afibrinogenemia (extremely low blood fibrinogen) and hypofibrinogenemia (low blood fibrinogen) in the general population [27].

This disorder sometimes coexists with plaque build-up in the kidneys that eventually leads to kidney failure [31].

Congenital hypodysfibrinogenemia is a relatively common inherited disorder that causes low fibrinogen levels and clotting problems.

Fibrinogen Storage Disease

Fibrinogen storage disease is a genetic disorder characterized by low blood levels of fibrinogen as well as a liver disease [32, 33, 34].

The liver disease is caused by excessive storage of fibrinogen in liver cells and is exclusively associated with dominant mutations in the FGG gene [34, 35, 32].

The disease typically manifests in childhood and is estimated to affect one person per 100 (single case study; genomic database analysis including approximately 140,000 people) [32, 25].

Fibrinogen storage disease is a genetic disorder that lowers fibrinogen levels and often leads to liver disease.

Health Risks of Low Fibrinogen

1) Excessive Bleeding and Slow Healing

The most common symptoms of low blood fibrinogen levels are prolonged bleeding and easy bruising, especially after traumatic injury or surgery [23].

Many people also experience longer healing times, spontaneous bruising in their muscles (hematomas), and occasional intestinal bleeding [36, 24].

People with very low blood levels of fibrinogen also likely to have spontaneous bleeding, especially around the gums and joints [28].

Low fibrinogen can increase your bleeding time. You may bruise easier and take longer to heal from injuries than people with normal fibrinogen levels.

2) Pregnancy Complications

Women with low fibrinogen blood levels are more likely to have abnormally heavy menstruation and pregnancy complications, which can lead to miscarriage [37, 38, 28, 39].

3) Harmful Blood Clots

Paradoxically, people with extremely low fibrinogen levels may actually be more susceptible to free-floating clots that block blood vessels. This may be because fibrinogen is not present to inhibit the formation of these internal clots [40, 41, 42, 43].

If your fibrinogen is low, you may be at risk of having large blood clots in your blood vessels. Women with low levels are at risk of pregnancy complications.


Most of the causal relationships between fibrinogen concentration and associated diseases remain unclear. More research is needed to make concrete conclusions about the effects of and effects on fibrinogen.

How to Increase Fibrinogen

1) Fibrinogen Replacement Therapy

Replacing fibrinogen is recommended to prevent and treat excessive bleeding, especially during pregnancy [44, 45, 46].

Depending on the region, replacement therapy may come in the form of plasma (blood)-derived fibrinogen concentrate of cryoprecipitate (frozen plasma containing high concentrations of fibrinogen) [47, 44].

If your fibrinogen is very low, your doctor may prescribe fibrinogen replacement therapy.

2) Diet

A survey of 1,854 people found that people with elevated blood levels of cholesterol and fatty acids also had high fibrinogen levels, indicating a diet that raises cholesterol may also increase fibrinogen [48].

Furthermore, diets high in iron, sugar, and caffeine were hypothesized to account for the increased fibrinogen levels in 206 Japanese emigrants in Hawaii [49].

Protein, in particular, may be necessary for healthy levels of fibrinogen. Protein-deficient animals have low fibrinogen compared to their properly-nourished counterparts [50].

A study of 16 individuals also found that fibrinogen increased by 20 to 40% directly after the participants drank a protein shake or balanced-meal shake, but not after drinking water [51].

However, giving your body the building blocks it needs to create fibrinogen may only help if your liver is healthy and if you don’t suffer from a genetic disease. If your ability to produce fibrinogen is compromised, you will likely need replacement therapy.

Getting more protein and iron may help lower fibrinogen levels in people without inborn disorders or liver problems. Others require fibrinogen replacement therapy.

Learn More

Irregular Fibrinogen Levels?

LabTestAnalyzer helps you make sense of your lab results. It informs you which labs are not in the optimal range and gives you guidance about how to get them to optimal. It also allows you to track your labs over time. No need to do thousands of hours of research on what to make of your lab tests.

LabTestAnalyzer is a sister company of SelfHacked. The proceeds from your purchase of this product are reinvested into our research and development, in order to serve you better. Thank you for your support.


When your fibrinogen is low, your body can’t create blood clots and heal injuries. Women with low levels are at risk of pregnancy complications.

Genetic disorders are a relatively common cause of low fibrinogen levels. In others, fibrinogen levels drop as a result of traumatic injuries and blood loss, liver disease, leukemia, or certain medications.

Your doctor will prescribe treatment based on the underlying cause. Some people require fibrinogen replacement therapy. Dietary changes may help if you don’t have a genetic disorder or serious illness.

Click here to subscribe


1 Star2 Stars3 Stars4 Stars5 Stars
(No Ratings Yet)

FDA Compliance

The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.