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Haemophilia

Haemophilia is a lifelong inherited bleeding disorder. In haemophilia one of the clotting factor proteins important for blood clotting is either partly or completely missing. People with haemophilia take longer than normal for bleeding to stop. They may have bleeding into joints and muscles without having had an injury, so treatment is aimed at reducing spontaneous bleeding.

There are two types of haemophilia:

  • haemophilia A is a deficiency of factor VIII (8)
  • haemophilia B (also known as Christmas Disease) is a deficiency of factor IX (9).

Both types of haemophilia have the same symptoms and are inherited in the same way, though treatment is different depending on which clotting factor is missing. Specialist blood tests are needed to measure the clotting factors to show whether factor VIII or factor IX is affected and how much is missing.

Haemophilia is classed as severe, moderate or mild depending on how much clotting factor is missing. The level of factor VIII or factor IX in the blood is measured by a specialist laboratory. In general, the lower the level, the more bleeding problems the affected person will have without treatment.

Females can also be affected with haemophilia.

ClassificationLevel of factor VIII or factor IX in the blood
(normal: 50-150%)
Typical bleeding tendency
SevereLess than 1% of normal levelEasy bruising including from mouth and nose.  
Bleeding into joints and muscles, which can be without obvious cause.
Bleeding after dental or surgical procedures or injuries including minor bumps and knocks.  
Moderate1 to 5% of normal levelEasy bruising.  
Bleeding because of minor injury.  
Occasional spontaneous bleeding.  
Likely to have problems after having dental or surgical procedures and/or a bad injury.
MildOver 5% of normal levelEasy bruising  
Bleeding usually only occurs following injury, surgical or dental (tooth extraction) procedures.  
Might never have a bleeding problem requiring medical attention. Might not be diagnosed until later in life if not playing contact sports or have not had any injuries or operations.  
Females may also have heavy or prolonged periods (menorrhagia).

More information is available in our Understanding Haemophilia booklet.

What causes haemophilia?

Haemophilia is an inherited condition. The genes responsible for producing factor VIII and IX are on the X chromosome.

Chance of a carrier having a son with haemophiliaEach of her sons will have a 50% (1 in 2) chance of having haemophilia
Chance of a carrier having a daughter who is a carrierEach of her daughters will have a 50% (1 in 2) chance of being a carrier
Chance of a man with haemophilia having a son with haemophiliaNone – unless the mother of his son is a carrier
Chance of a man with haemophilia having a daughter who is a carrierAll his daughters will be carriers

Females have two copies of the X chromosome and males have one X chromosome and one Y chromosome. The mother produces an egg containing one X chromosome. The father produces sperm, which could contain either an X or a Y chromosome. The fusion of a sperm with an egg creates the embryo which will grow into a child which then has two sex chromosomes. If the father contributes his X chromosome, a girl is conceived. If he contributes his Y chromosome, a boy is conceived.

If a man has an altered haemophilia gene on his X chromosome, then he will be affected with haemophilia. If a female has an altered haemophilia gene on only one of her X chromosomes, then she is known as a carrier. The term carrier can be misleading because some females who are carriers of haemophilia may have significantly reduced factor levels, which means they have a mild form of haemophilia themselves. You may hear doctors use the term heterozygote instead of carrier. The pattern of inheritance is known as sex- or X-linked recessive.

If a man has an altered haemophilia gene on his X chromosome, then he will be affected with haemophilia. If a female has an altered haemophilia gene on only one of her X chromosomes, then she is known as a carrier.

The term carrier can be misleading because some females who are carriers of haemophilia may have significantly reduced factor levels, which means they have a mild form of haemophilia themselves. You may hear doctors use the term heterozygote instead of carrier. The pattern of inheritance is known as sex- or X-linked recessive.

In some cases of haemophilia there is no known family history. This may be because the alteration to the haemophilia gene is new, known as a spontaneous mutation, or that no affected males have been known in the family.

More information is available in our Understanding Haemophilia booklet.

Signs and symptoms of haemophilia

People with haemophilia don’t cut more easily or bleed more quickly than normal. They do bleed for longer.  

Cuts and scratches

In most cases minor cuts and scratches aren’t a problem. A little pressure is usually enough to stop the bleeding.

Bruises

Bruises are common when children start to crawl or walk. They may get bruises on their knees and elbows as they progress to crawling and standing, or if they fall or roll onto a hard toy or surface. Once they begin to stand and walk, they may get bruising on their buttocks if they fall or sit down suddenly. The bruises may look serious, but they don’t usually need any treatment. However, if the bruise is swelling and painful then treatment may be helpful (see Joints and muscles below).  

Prolonged bleeding

People with haemophilia commonly have prolonged bleeding following larger cuts or minor surgery such as having a tooth out or a circumcision. This can last for several days. There’s no reason why anyone with haemophilia shouldn’t have surgery with the correct treatment.

Joints and muscles

In severe haemophilia the main problem is internal bleeding into joints and muscles. We all damage our tissues in small ways in the activities of everyday life and most people repair that damage automatically. With severe haemophilia, the tiny breaks in the blood vessels in joints and muscles may continue to bleed. These bleeds are sometimes described as ‘spontaneous’ because it’s impossible to identify an obvious reason such as a bump or a fall.

More information is available in our Understanding Haemophilia booklet.

How is haemophilia diagnosed and treated?

The diagnosis of haemophilia may be expected or suspected where there is a family history, or it may be completely unexpected. The following investigations lead to the diagnosis:

  • history, signs and symptoms of bleeding
  • family history of bleeding
  • family history of haemophilia
  • blood tests – a general test of blood clotting called a clotting screen which can be performed at all hospitals may suggest haemophilia and lead to referral for specific tests for factor VIII and factor IX.

Known haemophilia in the family

If there is a history of haemophilia in the family, it’s possible that parents will have had contact with the haemophilia team at their nearest centre and will have had the opportunity to talk about the options available to them before or during pregnancy. They will also often have known their baby’s sex before delivery.

If the haemophilia is severe in the family, then the delivery should have been carefully planned and a sample of blood taken from the baby’s umbilical cord shortly after birth to measure the factor VIII or factor IX level. Even with the knowledge that there is a 1 in 2 chance of a baby boy having haemophilia, it can take time to get used to the diagnosis. While the baby’s mother is likely to have a good understanding of the haemophilia in her family, this will be affected by family experience and may not be up to date with current treatment. The baby’s father may not have full knowledge of haemophilia and will seek guidance. The haemophilia team will aim to answer questions and give clear explanations to both parents.

If there is a family history of moderate or mild haemophilia, a blood sample can still be taken from the baby’s cord. However, since factor VIII and factor IX levels may not reach their normal baseline until the baby is six months old, the blood tests may need to be done again at that stage. This will give a clearer picture of how the child is likely to be affected by haemophilia.

No history of haemophilia in the family

For at least one-third of people newly diagnosed with haemophilia there is no family history.

Moderate and mild haemophilia may not be diagnosed until later in childhood or in some cases in adulthood.  The diagnosis may only be suspected  if there is bleeding after surgery or having a tooth out, or after an injury.

Treatment

Different types of treatments are available for managing haemophilia and may vary depending on how severe it is. Prompt, effective treatment and prevention of bleeding significantly reduces the risk of complications and disruptions to school, work and family life.

Treatment will be needed by everyone with haemophilia if they are bleeding. It will also be necessary to prevent bleeding if they need an operation or have an injury where there is a risk of bleeding.

More information is available in our Understanding Haemophilia booklet.

Pregnancy and Haemophilia

Prenatal diagnosis is usually offered to help with reproductive planning and risk assessment.  

If you know that haemophilia runs in your family, you may wish to have a test during pregnancy to find out the sex of your baby.

Free foetal DNA (ffDNA) is a blood test arranged by your haemophilia centre to find out the sex of your baby during the early stages of pregnancy. As early as nine weeks of pregnancy cells from your baby (foetal cells) can be detected in your blood and these are analysed to work out the baby’s sex. The test results take about a week and your haemophilia centre will contact you as soon as they have the results. If you don’t want to know the sex of your baby your haemophilia centre can still do the test but inform your obstetric team without telling you the results. At this stage, some women will choose not to continue their pregnancy, this should be discussed with the haemophilia doctor.  

If you are carrying a male foetus, you may then choose to have a test called chorionic villus sampling (CVS). CVS is a test where the doctor takes a sample of cells from the placenta. It is usually carried out between 11 and 14 weeks of a pregnancy. To do the test, the doctor puts a fine needle through the wall of your abdomen or a thin tube into your vagina and up into the womb. They can then take a small sample of cells from the placenta for genetic testing.

An additional possible test is amniocentesis. This means taking a sample of fluid from the womb, from inside the membrane holding the baby. The fluid contains cells from the baby that can be genetically tested. Amniocentesis is usually done later in pregnancy than CVS, from between 15 and 20 weeks until near the end of pregnancy.

There is a risk of miscarriage with CVS and amniocentesis tests – about 1 in 100. Your doctor will talk you through all the possible risks and what the test can show before you decide whether you want to go ahead. 

Management of care for all pregnant carriers should involve close cooperation between the haemophilia and obstetric teams. It is important to have a clear plan for delivery that is shared with the mother to be and kept in her medical notes

More information is available in our Understanding Haemophilia booklet.