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Introduction to hemophilia

Hemophilia is a bleeding problem. People with hemophilia do not bleed any faster than normal, but they can bleed for a longer time. Their blood does not have enough clotting factor. Clotting factor is a protein in blood that controls bleeding.

Hemophilia is quite rare. About 1 in 10,000 people are born with it.

Types of hemophilia

The most common type of hemophilia is called hemophilia A. This means the person does not have enough clotting factor VIII (factor eight).

Hemophilia B is less common. A person with hemophilia B does not have enough factor IX (factor nine). The result is the same for people with hemophilia A and B; that is, they bleed for a longer time than normal.

Updated May 2012

People are born with hemophilia. They cannot catch it from someone like a cold.

Hemophilia is usually inherited, meaning that it is passed on through a parent’s genes. Genes carry messages about the way the body’s cells will develop as a baby grows into an adult. They determine a person’s hair and eye colour, for example.

Sometimes hemophilia can occur when there is no family history of it. This is called sporadic hemophilia. About 30% of people with hemophilia did not get it through their parent’s genes. It was caused by a change in the person’s own genes.

How is hemophilia inherited?

The hemophilia gene is passed down from parent to child. The genes for hemophilia A and B are on the X chromosome. For this reason, hemophilia is called an X-linked (or sex-linked) disorder.

The figure below explains how the hemophilia gene is inherited. When the father has hemophilia but the mother does not, none of the sons will have hemophilia. All the daughters will carry the hemophilia gene.

If a woman inherits a copy of the altered gene from either of her parents, she is said to “carry” the hemophilia gene and is therefore called a “carrier.” In other words, she has one normal and one altered copy of the gene. She can pass either gene onto her children. For each child, there is a 50% chance that a son will have hemophilia and a 50% chance that a daughter will carry the gene. On average, carriers of hemophilia will have about 50 per cent of the normal amount of clotting factor, but some carriers have far lower levels of clotting factor.

Click here for more information on carriers and women with hemophilia.

Acquired hemophilia

In rare cases, a person can develop hemophilia later in life. The majority of cases involve middle-aged or elderly people, or young women who have recently given birth or are in the later stages of pregnancy. This condition often resolves with appropriate treatment.

Updated September 2016

The severity describes how serious a problem is. The level of severity depends on the amount of clotting factor that is missing from a person’s blood.

Level Percentage of normal factor activity in blood Number of international units (IU) per millilitre (ml) of whole blood
Normal range  50%–150%   0.50–1.5 IU
Mild hemophilia  5%–40%   0.05–0.40 IU
Moderate hemophilia   1%–5%   0.01­–0.05 IU
Severe hemophilia   Less than 1%   Less than 0.01 IU

People with severe hemophilia usually bleed frequently into their muscles or joints. They may bleed one to two times per week. Bleeding is often spontaneous, which means it happens for no obvious reason.

People with moderate hemophilia bleed less frequently, about once a month. They may bleed for a long time after surgery, a bad injury, or dental work. A person with moderate hemophilia will rarely experience spontaneous bleeding.

People with mild hemophilia usually bleed as a result of surgery or major injury. They do not bleed often and, in fact, some may never have a bleeding problem.

Updated May 2012

The signs of hemophilia A and B are the same:

  • Big bruises
  • Bleeding into muscles and joints
  • Spontaneous bleeding (sudden bleeding inside the body for no clear reason)
  • Prolonged bleeding after getting a cut, removing a tooth, or having surgery
  • Bleeding for a long time after an accident, especially after an injury to the head

Bleeding into a joint or muscle causes:

  • An ache or “funny feeling”
  • Swelling
  • Pain and stiffness
  • Difficulty using a joint or muscle

Where does bleeding occur?

People with hemophilia can bleed inside or outside the body. Most bleeding in hemophilia occurs internally, into the muscles or joints. The most common muscle bleeds occur in the muscles of the upper arm and forearm, the iliopsoas muscle (the front of the groin area), the thigh, and the calf. The joints that are most often affected are the knee, ankle, and elbow.

If bleeding occurs many times into the same joint, the joint can become damaged and painful.

Repeated bleeding can cause other health problems like arthritis. This can make it difficult to walk or do simple activities. However, the joints of the hands are not usually affected in hemophilia (unlike some kinds of arthritis).

How is hemophilia diagnosed?

Hemophilia is diagnosed by taking a blood sample and measuring the level of factor activity in the blood. Hemophilia A is diagnosed by testing the level of factor VIII activity. Hemophilia B is diagnosed by measuring the level of factor IX activity.

If the mother is a known carrier of hemophilia, testing can be done before a baby is born. Prenatal diagnosis can be done at 9 to 11 weeks by chorionic villus sampling (CVS) or by fetal blood sampling at a later stage (18 or more weeks).

These tests can be done at a hemophilia treatment centre.

Consult the Global Treatment Centre Directory for information on treatment centres around the world.

Updated May 2012

Treatment for hemophilia today is very effective. The missing clotting factor is injected into the bloodstream using a needle. Bleeding stops when enough clotting factor reaches the spot that is bleeding.

Bleeding should be treated as quickly as possible. Quick treatment will help reduce pain and damage to the joints, muscles, and organs. If bleeding is treated quickly, less blood product is needed to stop the bleeding.

With an adequate quantity of treatment products and proper care, people with hemophilia can live perfectly healthy lives. Without treatment, most children with severe hemophilia will die young. An estimated 400,000 people worldwide are living with hemophilia and only 25% receive adequate treatment. The World Federation of Hemophilia is striving to close this gap.

Treatment products

Factor concentrates are the treatment of choice for hemophilia. They can be made from human blood (called plasma-derived products) or manufactured using genetically engineered cells that carry a human factor gene (called recombinant products). Factor concentrates are made in sophisticated manufacturing facilities. All commercially prepared factor concentrates are treated to remove or inactivate blood-borne viruses.

Cryoprecipitate is derived from blood and contains a moderately high concentration of clotting factor VIII (but not IX). It is effective for joint and muscle bleeds, but is less safe from viral contamination than concentrates and is harder to store and administer. Cryoprecipitate can be made at local blood collection facilities.

In fresh frozen plasma (FFP) the red cells have been removed, leaving the blood proteins including clotting factors VIII and IX. It is less effective than cryoprecipitate for the treatment of hemophilia A because the factor VIII is less concentrated. Large volumes of plasma must be transfused, which can lead to a complication called circulatory overload. FFP is still the only product available for treatment of hemophilia A and B in some countries.

People with mild hemophilia A may sometimes use desmopressin (also called DDAVP) to treat minor bleeding. DDAVP is a synthetic hormone that stimulates the release of factor VIII.

New panel discussion: New developments in treatment for bleeding disorders—novel therapies; is a cure for hemophilia around the corner?

While clotting factor concentrates remain, by far, the mainstay of the management of hemophilia, a number of novel therapies under development have the potential to dramatically change the treatment landscape. Leading hematologists and patient advocates from around the world debate the potential of factor mimetics, antithrombin therapies, and gene therapy to change the lives of all people living with bleeding disorders.

Panel: David Lillicrap, Edward Tuddenham, Glenn Pierce, Declan Noone, chaired by David Page.

The opinions expressed in this video are those of the individual panelists and not the official position of the World Federation of Hemophilia.
Updated March 2016

What is the difference between hemophilia A and hemophilia B?

The most common type of hemophilia is called hemophilia A. This means the person does not have enough clotting factor VIII (factor eight).

A less common type is hemophilia B. This person does not have enough clotting factor IX (factor nine).

The result is the same for people with hemophilia A and B: they both bleed for a longer time than normal.

Is hemophilia lifelong?

A person born with hemophilia will have it for life. The level of factor VIII or factor IX in the blood usually stays the same throughout the person’s life.

How common is hemophilia?

Hemophilia is quite rare. About 1 in 10,000 people is born with hemophilia A. About 1 in 50,000 people is born with hemophilia B.

Are there other types of bleeding disorders?

Yes, there are several other factor deficiencies that also cause abnormal bleeding. These include deficiencies in factors I, II, V, VII, X, XI, XIII, and von Willebrand factor. The most severe forms of these deficiencies are even rarer than hemophilia A and B.

More information on von Willebrand disease, rare clotting factor deficiencies, and inherited platelet disorders.

How serious is hemophilia?

The severity of hemophilia depends on the amount of factor VIII or factor IX in the blood.

There are three levels of severity: mild, moderate, and severe. People with severe hemophilia usually bleed frequently into their muscles or joints. They may bleed one to two times per week. Bleeding is often spontaneous, which means it happens for no obvious reason.

People with moderate hemophilia bleed less often, usually after an injury. Cases of hemophilia vary, however, and a person with moderate hemophilia can bleed spontaneously.

People with mild hemophilia usually bleed only as a result of surgery or major injury.

What is acquired hemophilia?

In rare cases, a person can develop hemophilia later in life. The majority of cases involve middle-aged or elderly people, or young women who have recently given birth or are in the later stages of pregnancy.

Acquired hemophilia is usually caused by the development of antibodies to factor VIII or factor IX: the body’s immune system destroys its own naturally produced factor VIII.

This condition often resolves with appropriate treatment.

Does hemophilia only affect men?

For many years, people believed that only men could have symptoms of hemophilia and that women who “carry” the hemophilia gene do not experience symptoms themselves. We now know that many carriers do experience symptoms of hemophilia. As our knowledge about the disorder has increased, so has our understanding of why and how women can be affected. A woman who has less than 40 per cent of the normal level of clotting factor is no different from a man with the same factor levels—she has hemophilia. Some carriers have symptoms of hemophilia even though their clotting factor levels are above 40 per cent. A woman with levels of 40-60 per cent of the normal amount of clotting factor who experiences abnormal bleeding is called a symptomatic carrier.

Click here for more information on carriers and women with hemophilia.

Are there any precautions a carrier of hemophilia should take if she becomes pregnant?

A carrier’s hematologist should be involved in the supervision of the pregnancy and should consult with the obstetrician before delivery. It is not necessary to perform prenatal diagnosis just for management of the pregnancy. This is only done if termination of pregnancy is being considered in the case of an affected child.

The factor VIII level (but not factor IX) tends to rise during pregnancy but should be checked sometime in the month or so before delivery.

A normal vaginal delivery is perfectly acceptable even if the fetus is male and at risk of hemophilia. Epidural anesthesia does not usually present a problem and is generally possible if the patient’s factor level is 40% or more. A cord blood sample after delivery will be used to check if a male baby has hemophilia.

How is hemophilia diagnosed?

Hemophilia is diagnosed by taking a blood sample and measuring the level of factor activity in the blood. Hemophilia A is diagnosed by testing the level of factor VIII coagulation activity in the blood. Hemophilia B is diagnosed by measuring the level of factor IX activity.

If the mother is a carrier, testing can be done before a baby is born. Prenatal diagnosis can be done at 9 to 11 weeks by chorionic villus sampling (CVS) or by fetal blood sampling at a later stage (18 or more weeks).

These tests can be done at a hemophilia treatment centre. Consult the Global Treatment Centre Directory for information on treatment centres around the world.

Where do bleeds occur?

Most bleeding in hemophilia occurs internally, into the joints or muscles.

The joints that are most often affected are the knee, ankle, and elbow. Repeated bleeding without prompt treatment can damage the cartilage and the bone in a joint, leading to chronic arthritis and disability.

The most serious muscle bleeds are the iliopsoas muscle (the front of the groin area), the forearm, and the calf.

Some bleeds can be life-threatening and require immediate treatment. These include bleeds in the head, throat, gut, or iliopsoas.

Are bruises dangerous?

Bruises are very common in children with hemophilia. A bruise is not usually cause for alarm, unless it is on the person’s head or neck, the person has a hard time moving, the bruise hurts, the lump in the bruise gets larger or does not go away, or if there is numbness or a tingling feeling along with the bruising. In any of these cases, a physician or local hemophilia treatment centre should be consulted.

Should people with hemophilia avoid aspirin and other similar non-steroidal anti-inflammatory drugs (NSAIDs)?

People with hemophilia should not take aspirin (ASA or acetylsalicyclic acid), or anything containing aspirin, as well as other NSAIDs, because they interfere with the stickiness of platelets and can make bleeding problems worse. Paracetamol (acetominophen) is a perfectly safe alternative to aspirin to relieve pain.

A list of medications that can interfere with bleeding.

Should people with hemophilia exercise and play sports?

Some people with hemophilia avoid exercise because they think it may cause bleeds, but exercise can actually help prevent them. Strong muscles help protect someone who has hemophilia from spontaneous bleeds and joint damage.

Sport is an important activity for young people. It helps build muscle and develop mental concentration and coordination. However, some sports are riskier than others, and the benefits must be weighed against the risks. The severity of a person’s hemophilia should also be considered when choosing a sport. Sports like swimming, badminton, cycling, and walking are safe for most people with hemophilia, while American football, rugby, and boxing are usually not recommended.

What are inhibitors?

Inhibitors are a serious medical problem that can occur when a person with hemophilia has an immune response to treatment with clotting factor concentrates.

Sometimes, a person’s immune system reacts to proteins in factor concentrates as if they were harmful foreign substances because the body has never seen them before. When this happens, inhibitors (also called antibodies) form in the blood to fight against the foreign factor proteins. This stops the factor concentrates from being able to fix the bleeding problem.

Bleeding is very hard to control in someone with hemophilia who develops inhibitors.

More information on inhibitors.

What is prophylaxis?

Prophylaxis is the regular use of clotting factor concentrates to prevent bleeds before they start. Injections of clotting factor are given one, two, or three times a week to maintain a constant level of factor VIII or IX in the bloodstream.

Prophylaxis can help reduce or prevent joint damage and improve the quality of life of people with hemophilia. In countries with access to adequate quantities of clotting factor concentrates, this is becoming the normal mode of treatment for younger patients, and can be started when the veins are well developed (usually between the ages of two and four years).

For more information on prophylaxis, click here.

What is a venous access device (Port-a-Cath)?

A Port-a-Cath, or implantable venous access device (VAD), is a device that’s implanted under the skin, usually in the chest but sometimes in the arm. It has a reservoir connected to a catheter, which is then threaded into a vein. This way, medications and fluids can be injected easily, without having to find a vein for each injection.

VADs have made prophylaxis (regular infusions of factor concentrates) in hemophilia much easier for families. However, there are risks. Some studies have shown an infection rate as high as 50%. These infections can usually be treated with intravenous antibiotics but sometimes the device must be removed. There is also a risk of clots forming at the tip of the catheter. Like for any other procedure, each family must weigh the risks and benefits.

Is there a cure for hemophilia?

There is no cure for hemophilia. Gene therapy remains an exciting possibility and holds out the prospect of a partial or complete cure. There are many technical obstacles to overcome, but research currently underway is encouraging.

Technically, a liver transplant can cure hemophilia, since coagulation factors are produced by cells inside the liver. However, the risks of surgery and the requirement for lifelong medication to prevent rejection of the transplanted organ may outweigh the benefits.

What is the life expectancy of someone with hemophilia?

The life expectancy of someone with hemophilia varies depending on whether they receive proper treatment. Without adequate treatment, many people with hemophilia die before they reach adulthood. However, with proper treatment, life expectancy for people with hemophilia is about 10 years less than that of males without hemophilia, and children can look forward to a normal life expectancy.

Updated May 2012