How severe is haemophilia?
There are three levels of severity in haemophilia:
The severity of haemophilia depends on the amount of clotting factor in the person’s blood.
Can a person’s factor level change?
A person with haemophilia will usually have the same level of severity over their lifetime, eg a person with severe haemophilia will always have severe haemophilia. Within a family, males with haemophilia will also nearly always have the same level of severity, eg if a grandfather has severe haemophilia and his grandson has inherited haemophilia, his grandson will also have severe haemophilia. However, factor levels in females affected by haemophilia are unpredictable and severity can vary between females and other family members.
It may take some time after birth to confirm a child’s factor level while their factor levels stabilise. Factor VIII (8) levels can also change for females with pregnancy and hormonal medications such as the contraceptive pill and as they grow older. Factor IX (9) levels rarely change in people with haemophilia B.
Can a female have bleeding problems with a normal factor level?
Some females who carry the gene alteration and have factor levels at the lower end of normal (40-50%) may also experience abnormal bleeding. If further investigation indicates the bleeding is related to haemophilia, they will be treated as having mild haemophilia and diagnosed as symptomatic haemophilia carriers.
What is a normal factor level?
The normal level of factor VIII or IX in a person’s blood is between 50% and 150%.
|What to expect if you have haemophilia
Mild haemophilia5% – 40% of normal clotting factor level
|Moderate haemophilia1% – 5% of normal clotting factor level
|Severe haemophiliaLess than 1% of normal clotting factor level
Please note: this table is a guide only.