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von Willebrand disease (VWD) is the most common type of bleeding disorder. People with VWD have a problem with a protein in their blood called von Willebrand factor (VWF) that helps control bleeding. When a blood vessel is injured and bleeding occurs, VWF helps cells in the blood, called platelets, mesh together and form a clot to stop the bleeding. People with VWD do not have enough VWF, or it does not work the way it should. It takes longer for blood to clot and for bleeding to stop.
VWD is generally less severe than other bleeding disorders. Many people with VWD may not know that they have the disorder because their bleeding symptoms are very mild. For most people with VWD, the disorder causes little or no disruption to their lives except when there is a serious injury or need for surgery. However, with all forms of VWD, there can be bleeding problems.
It is estimated that up to 1% of the world’s population suffers from VWD, but because many people have only very mild symptoms, only a small number of them know they have it. Research has shown that as many as 9 out of 10 people with VWD have not been diagnosed.
There are three main types of VWD. Within each type, the disorder can be mild, moderate, or severe. Bleeding symptoms can be quite variable within each type depending in part on the VWF activity. It is important to know which type of VWD a person has, because treatment is different for each type.
Type 1 VWD is the most common form. People with Type 1 VWD have lower than normal levels of VWF. Symptoms are usually very mild. Still, it is possible for someone with Type 1 VWD to have serious bleeding.
Type 2 VWD involves a defect in the VWF structure. The VWF protein does not work properly, causing lower than normal VWF activity. There are different Type 2 VWD defects. Symptoms are usually moderate.
Type 3 VWD is usually the most serious form. People with Type 3 VWD have very little or no VWF. Symptoms are more severe. People with Type 3 VWD can have bleeding into muscles and joints, sometimes without injury.
VWD is usually inherited. It is passed down through the genes from either parent to a child of either sex. Sometimes, there is evidence of a family history of bleeding problems, but the symptoms of VWD can vary a lot within a family. Sometimes VWD occurs due to a spontaneous change in the VWD gene before the baby is born.
VWD Types 1 and 2 are usually inherited in what is known as a “dominant” pattern. This means that a parent who has VWD has a one in two (50%) chance of passing a VWD gene on to each of his or her children.
Type 3 VWD, however, is usually inherited in a “recessive” pattern. This type occurs when the child inherits the gene from both parents. Even if both parents have mild symptoms or no symptoms at all, their children may be severely affected.
Many people with VWD have few or no symptoms. People with more serious VWD may have more bleeding problems. Symptoms can also change over time. Sometimes VWD is discovered only when there is heavy bleeding after a serious accident or a dental or surgical procedure.
The main symptoms of VWD are:
More women than men show symptoms of VWD. Women with VWD often bleed more or longer than normal with menstruation and following childbirth. Some women with VWD have a lot of menstrual pain or irregular menstruation.
Blood type can play a role. People with Type O blood often have lower levels of VWF than people with Types A, B, and AB. This means people with VWD and Type O blood may have more problems with bleeding.
VWD is not easy to diagnose. People who think they have a bleeding problem should see a hematologist who specializes in bleeding disorders. Proper tests can be done at a bleeding disorders treatment centre. Since the VWF protein has more than one function, more than one lab test should be used to diagnose VWD.
Testing involves measuring a person’s level and activity of VWF, and that of another blood clotting protein, factor VIII (FVIII). Testing is often repeated because a person’s VWF and FVIII levels can vary at different times.
Some of the tests that may be performed include:
| Test | Purpose |
|---|---|
| Bleeding time | Measures how long it takes for bleeding to stop |
| Factor VIII clotting activity | Measures how well factor VIII works |
| von Willebrand factor antigen | Measures the amount of VWF |
| Ristocetin co-factor and/or collagen binding activity | Measures how well VWF works |
| von Willebrand factor multimers | Measures how the individual molecules of VWF come together (groups of VWF molecules are called multimers) and break apart |
| Platelet function tests (e.g. PFA*-100) *platelet function analyser |
Measure how well platelets work |
VWD can be treated with a synthetic drug called desmopressin, with a clotting factor concentrate that contains VWF, or with other drugs that help control bleeding. The type of treatment depends in part on the type of VWD a person has. People with mild forms of VWD often do not require treatment for the disorder except for surgery or dental work.
Desmopressin is generally effective for treating Type 1 VWD, and helps prevent or treat bleeding in some forms of Type 2 VWD. It is used to control bleeding in an emergency or during surgery. It can be injected or taken by nasal spray, and raises VWF and FVIII levels to help blood clot. Desmopressin does not work for everyone. A doctor needs to do tests to find out if an individual responds to the drug. Ideally, tests should be done before treatment is needed.
Factor concentrates are used when desmopressin is not effective or when there is a high risk of major bleeding. Factor concentrates contain VWF and FVIII. This is the preferred treatment for Type 3 VWD, most forms of Type 2 VWD, and for serious bleeding or major surgery in all types of VWD.
Bleeding in mucous membranes (inside the nose, mouth, intestines or womb) can be controlled by drugs such as tranexamic acid, aminocaproic acid, or by fibrin glue. However, these products are used to maintain a clot and do not actually help form a clot.
Hormone treatment, such as oral contraceptives (birth control pills), helps increase VWF and FVIII levels and control menstrual bleeding. If hormone treatment is not prescribed, antifibrinolytic agents may be effective for treating heavy menstruation. Women who suffer from anemia (low levels of iron in the blood, causing weakness and fatigue) due to excessive menstrual bleeding may need to take iron supplements.
These treatments may have side effects, so people with VWD should talk to their physician about possible side effects of treatment.
Women with VWD tend to have more symptoms than men because of menstruation and childbirth. Girls may have especially heavy bleeding when they begin to menstruate. Women with VWD often have heavier and/or longer menstrual flow. This heavier menstrual flow can cause anemia (low levels of iron in the blood, causing weakness and fatigue). Women with VWD should be checked regularly for anemia.
Every woman is different, and what is considered “normal” for one woman may be “excessive” for another. The average amount of blood lost during a “normal” period is 30–40 ml. Blood loss of 80 ml or more is considered heavy.
Of course, the amount of blood lost can be difficult to measure. If you believe you may suffer from excessive bleeding, complete the assessment chart during your next period. This is only a guide, but it can be a useful tool for you and your doctor to use when assessing your menstrual flow.
A woman with VWD should see an obstetrician as soon as she suspects she is pregnant. The obstetrician should work with a bleeding disorders treatment centre to provide the best care during the pregnancy and childbirth. During pregnancy, women experience an increase in VWF and FVIII levels. This provides better protection from bleeding during delivery. However, after delivery, these clotting factor levels fall quickly and bleeding can continue for longer than normal.
Women with VWD entering menopause (end of menstruation, usually between the ages of 45 and 50) are at increased risk of unpredictable and heavy bleeding. It is important for a woman with VWD to maintain a strong relationship with her gynecologist as she approaches menopause.
VWD is the most common type of bleeding disorder. People with VWD have a problem with a protein in their blood called von Willebrand factor (VWF) that helps control bleeding. When a blood vessel is injured and bleeding occurs, VWF helps cells in the blood, called platelets, mesh together and form a clot to stop the bleeding. People with VWD do not have enough VWF, or it does not work the way it should. It takes longer for blood to clot and for bleeding to stop.
In 1926, Dr. Erik von Willebrand, a Finnish physician, published the first description of an inherited bleeding disorder that was different from hemophilia. Dr. von Willebrand’s studies into this new disease began with a family living on the island of Föglö in the Åland archipelago in the Baltic Sea. One of the women (the first known sufferer of VWD) in this family bled to death in her teens from menstrual bleeding, and four other family members had also died before her as a result of uncontrolled bleeding.
It is estimated that up to 1% of the world’s population suffers from VWD, but because many people have only very mild symptoms, only a small number of them know they have it. Research has shown that as many as 9 out of 10 people with VWD have not been diagnosed.
VWD is usually inherited. It is passed down through the genes from either parent to a child of either sex. Occasionally, VWD occurs due to a spontaneous change in the VWD gene before the baby is born.
A woman with VWD has a 50% chance of passing the disease on to her child. If the father has VWD, the child still has a 50% chance of inheriting the disease.
VWD and hemophilia are different types of bleeding disorders. VWD is caused by a problem with von Willebrand factor, whereas hemophilia is caused by a problem with another type of clotting factor (factor VIII in hemophilia A; factor IX in hemophilia B). Though both disorders are usually inherited, the inheritance pattern (the way the genes are passed down from parent to child) is different. Symptoms of VWD are usually milder than symptoms of hemophilia, but serious bleeding episodes can occur in either condition.
The severity of symptoms depends partly on the type of VWD a person has. Types 1 and 2 are generally mild, but people with Type 3 VWD can have very serious bleeding episodes. Even within each type of VWD, though, symptoms can be quite variable.
More women than men show symptoms of VWD because of menstruation and childbirth. Women with VWD often bleed more or longer than normal with their monthly periods. However, men can also have serious symptoms, especially those with Type 3 VWD.
No. There are many possible reasons for heavy menstrual bleeding (menorrhagia) besides VWD. However, one British study showed that one out of every five women who went to the doctor because of heavy or prolonged bleeding actually had a bleeding disorder.
VWD is diagnosed through a series of blood tests that should be performed by specialists at a bleeding disorder treatment centre. Several different tests need to be done in order to determine the exact type of VWD a person has.
The diagnosis of VWD is difficult. Research has shown that as many as 9 out of 10 people with VWD have not been diagnosed.
Yes. Most women with VWD have no problem conceiving. Women with VWD should consult an obstetrician as soon as they learn they are pregnant. The obstetrician will work with the bleeding disorders treatment centre to provide the best care during the pregnancy and childbirth.
Women with Type 3 VWD seem to have more frequent miscarriages, especially in the first trimester of pregnancy. However, it is possible that these miscarriages are simply more noticeable in women with VWD, because there is more bleeding. Bleeding after miscarriage can also be more severe for women with VWD.
Yes. The hepatitis B vaccine is recommended for all people who routinely receive blood or blood products, even though the risk of transmission is very small. People with VWD, especially those who also have hepatitis C, should also get vaccinated against hepatitis A. In very rare cases, hepatitis A has also been transmitted by blood products.
No, there is no cure for VWD. It is a lifelong condition, but there are safe, effective treatments for all types of VWD.
© 2023 Всемирная федерация гемофилии