Bleeding disorders … what are they?
Bleeding disorders are conditions in which a person’s blood lacks certain proteins, called clotting factors, that help form clots. Clots are needed to stop or slow bleeding.
Normal blood clotting involves as many as 20 different clotting factors. These proteins act together to make a sticky web called fibrin. The fibrin traps platelets to form a clot. When certain clotting factors are missing or not enough is produced by the body, the person will have a bleeding disorder. Bleeding disorders can be mild, moderate or severe.
Some bleeding disorders are inherited, meaning that the baby is born with the disorder. Inherited conditions are passed to us through our genes.
Other bleeding disorders are acquired, which means they develop over time. Some causes of acquired bleeding disorders include:
- Vitamin K deficiency
- Severe liver disease
- Long-term use of antibiotics (drugs to fight infection)
- Long-term use of anticoagulants (drugs used to stop blood clots)
Rare platelet disorders are another type of bleeding disorder. They can also be either inherited or acquired after birth. They can last a short time or a lifetime as a chronic condition. On the average, platelet disorders are usually milder than the other types of bleeding disorders.
Why is it important to know about bleeding disorders?
Bleeding disorders in women of childbearing age are a major public health concern. Two out of every 10 women who have heavy periods, called menorrhagia, have an underlying bleeding disorder. This means about 1.5 to 4 million American women may have an undiagnosed bleeding disorder. [James]
If a woman has a bleeding disorder but does not know it, she may be at risk for complications after childbirth, injury or surgery. Complications can be managed or completely avoided if the woman is properly diagnosed and treated. Her quality of life can be improved. Getting diagnosed is the first step.
What are the most common bleeding disorders?
The most common bleeding disorders are von Willebrand disease and hemophilia.
Von Willebrand disease
Von Willebrand disease (VWD) is the most common bleeding disorder. It affects men and women equally.
- VWD affects up to 2 out of every 10 women with heavy periods.
- 9 out of every 10 of women with VWD have heavy periods.
- People with VWD do not have enough von Willebrand factor, another protein that helps your blood clot.
- Many variations of VWD have been identified, but most fall under the following classifications:
- Type 1
- Type 2
- Subtype 2A
- Subtype 2B
- Subtype 2M
- Subtype 2N
- Type 3
VWD is a hereditary or genetic condition, which means the gene for the condition is passed from parent to child. Patterns of inheritance are different for each type of VWD. Males and females have an equal chance of inheriting the gene and developing VWD. [James]
- Type 1 and rare cases of type 2 VWD are inherited in an autosomal dominant pattern, which means one copy of the altered or mutated gene in each cell is enough to cause the condition.
- Type 3 and most cases of type 2 VWD are inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have the mutation. Most often, the parents of a person with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs or symptoms of the condition.
Hemophilia is another genetic, or inherited, bleeding disorder that affects women. The gene for hemophilia is on the X chromosome. Females have two X chromosomes (XX). Males have one X and one Y chromosome (XY). Because the gene for hemophilia is on the X chromosome it is called an X-linked disease. Females who have the gene for hemophilia can pass the gene to their child through their X chromosome.
The following diagram shows the four possible outcomes for the baby of a woman who is a carrier.
These four possibilities are repeated for each and every pregnancy. So, if you have one son with hemophilia, it doesn’t mean your next son will not have it. If you have four children, it doesn’t mean two will have hemophilia and two will not.
- a boy who has hemophilia (1 in 4 chance)
- a boy who does not have hemophilia (1 in 4 chance)
- a girl who is a carrier (1 in 4 chance)
- a girl who is not a carrier (1 in 4 chance)
Hemophilia usually affects males more severely than females. The chance that a female will have severe hemophilia is about 1 in a million. Females who carry the gene for hemophilia (“carriers”) can have mild hemophilia. This is because they have low levels of clotting factor in their blood.
There are two types of hemophilia.
- Hemophilia A is the most common type. It affects about 8 out of every 10 of people with hemophilia. It is also known as factor VIII deficiency or classic hemophilia.
- Hemophilia A is caused by abnormally low levels of a protein called factor VIII (factor 8)
- In about 1 out of every 3 cases there is no family history of hemophilia and the condition is the result of a new spontaneous gene mutation
- Hemophilia B is caused by low levels of another protein needed for clotting called factor IX (factor 9). It is also called Christmas disease.
Worldwide, hemophilia affects all races and ethnic groups equally.
Other bleeding disorders
Rare Factor Disorders: There are several inherited bleeding disorders that are rare. In some of these disorders, one or more clotting factors are missing in the blood. Sometimes there are insufficient amounts of clotting factors, or the factors don’t work properly. These include:
- Factor I (1) deficiency
- Factor II (2) deficiency
- Factor V (5) deficiency
- Combined factor V (5) and VIII (8) deficiency
- Factor VII (7) deficiency
- Factor X (10) deficiency
- Factor XI (11) deficiency
- Factor XIII (13) deficiency
Rare Platelet Disorders: There are several rare bleeding disorders in which platelets lack a protein needed for blood to clot. These include:
- Bernard-Soulier Syndrome (BSS): a very rare platelet disorder that causes a deficiency of glycoprotein lb, the receptor for von Willebrand factor, which is important in clot formation. A person with BSS can bleed for a very long time before a clot forms. In fact, it may take more than 20 minutes for the bleeding to stop from even a small cut.
- Glanzmann’s Thrombasthenia (GT): an extremely rare bleeding disorder in which the platelets lack glycoprotein IIb/IIIa, the binding sites for von Willebrand factor, on the surface. In people with GT, platelets do not adhere, or stick to each other, as they should. Bleeding continues significantly longer than normal.
- Platelet Storage Pool Disease (SPD): a name given to several rare disorders in which the platelet granules are affected. During the process of making a platelet plug, the platelets change shape. Chemicals inside the granules are pushed out, or secreted into the bloodstream, signaling other platelets to migrate to the site of the plug. In SPD, a certain type of granule in the platelets may be missing or be abnormal. The result is that the body takes longer to form a clot.
Connective Tissue Disorders: Some connective tissue disorders can also cause bleeding disorders in women. Connective tissue supports the skin, bones, blood vessels and other organs [Kadir]. It is important to talk to your healthcare provider if you think you may have a connective tissue disorder so you can receive the proper diagnosis and treatment.
- Ehlers-Danlos syndrome (EDS). With EDS, connective tissue becomes weak. This can cause fragile, sagging skin, and loose joints.
- Epidermolysis bullosa (EB). With these disorders, the skin blisters when it is stressed. For example, a hug could cause a blister.
- Marfan syndrome. This disorder can affect the heart, blood vessels, lungs, eyes, bones and ligaments. People with this syndrome may be unusually tall and thin, with abnormally? long arms and legs.
- Osteogenesis imperfecta (OI). People with this disorder have bones that break easily, sometimes for no obvious reason.
Visit these Web sites if you would like more in-depth information about bleeding disorders:
National Hemophilia Foundation’s main Web site: www.hemophilia.org
National Hemophilia Foundation’s site, Steps for Living, has information on bleeding disorders at:
The U.S. Department of Health and Human Services has an Office of Women’s Health. You can find its Bleeding Disorders Fact Sheet at:
The U.S. Centers for Disease Control and Prevention (CDC) answers the question, “What Should You Know About Blood Disorders in Women?” at:
The U.S. Library of Medicine provides a “Guide to Understanding Genetic Conditions.” You can read more about Von Willebrand disease (VWD) at:
The U.S. Library of Medicine provides information about other blood conditions at:
Watch a video on how blod clots:
James, et al. American Journal of Obstetrics and Gynecology, 2004;191:449-455
Kadir RA, Economides DL, Sabin CA, Pollard D, Lee CA. Assessment of menstrual blood loss and gynaecological problems in patients with inherited bleeding disorders. Haemophilia. 1999;5:40–48