Hemophilia is an inherited bleeding disorder. A lack of or low levels of certain proteins called “clotting factors” characterizes the disorder.

There are several types of hemophilia, though they all have low levels of either clotting factor VIII or factor IX. Doctors base the overall severity of the condition on how much factor is present in the blood.

If you have hemophilia, your blood doesn’t clot properly as a result. This can lead to excessive bleeding, even from minor cuts or injuries. It can also cause:

  • spontaneous bleeding
  • internal bleeding
  • painful, swollen joints due to bleeding within them

The exact number of people living with hemophilia is not known. However, the Centers for Disease Control and Prevention (CDC) estimates that about 400 male babies are born each year with hemophilia A, a type of hemophilia.

The three forms of hemophilia include hemophilia A, B, and C.

  • Hemophilia A. Type A is the most common type of hemophilia. A deficiency in factor VIII causes this form of hemophilia, which is also known as “classic hemophilia.“
  • Hemophilia B. This type of hemophilia, also known as Christmas disease, occurs because clotting factor IX is missing or severely deficient.
  • Hemophilia C. Hemophilia C, also known as “factor XI deficiency,“ is a rare form of hemophilia first discovered in 1953 in people with severe bleeding after dental extractions.

Hemophilia is an inherited genetic condition. This condition isn’t curable, but it can be treated to minimize symptoms and prevent future health complications.

Congenital hemophilia

The majority of hemophilia cases are congenital. Congenital means that you acquire the trait from one or both of your parents when you’re born. About two-thirds of all type A and B cases of hemophilia occur in people with a family history of the condition.

Acquired hemophilia

Unlike congenital hemophilia, you can develop acquired hemophilia with no personal or family history of hemophilia. Instead, acquired hemophilia is a rare autoimmune disorder.

An autoimmune disorder or disease occurs when your immune system attacks healthy cells. In the case of acquired hemophilia, the immune system creates antibodies that attack the clotting factors, most frequently factor VIII (acquired hemophilia A).

The symptoms of hemophilia vary based on the severity of the condition.

There are three levels of severity associated with hemophilia A and B. Each level has its own associated symptoms.

Hemophilia C is generally considered to be a mild form of hemophilia, which means its symptoms and signs align with those of mild cases of A or B.

The symptoms for both types A and B are the same for each level.

Mild cases of hemophilia A or B typically include:

  • bleeding after surgery, injury, or tooth extraction
  • heavy menstrual bleeding
  • hemorrhaging following childbirth

Since symptoms do not occur until an incident happens, doctors may not diagnose mild forms of hemophilia until a person reaches adulthood.

In moderate cases of hemophilia A or B, severe bleeding typically occurs following an injury.

Finally, in severe cases of hemophilia A or B, you may experience:

  • bleeding following an injury
  • spontaneous bleeding into the joints or muscles

Often, a doctor can diagnose the condition following a circumcision shortly after birth.

In general, the CDC notes that signs of hemophilia can often include:

  • bleeding into the joints
  • bruising, bleeding into the skin
  • bleeding into the muscle and soft tissue
  • blood in stool or urine
  • bleeding after a shot
  • frequent, difficult to stop nosebleeds
  • bleeding in gums or mouth

The primary cause of all types of hemophilia is a mutation in the genes that control and regulate the development of clotting factors. Clotting factors help the blood form clots that seal up wounds.

For both hemophilia A and B, about two-thirds of the mutations come from a parent. The remaining can occur as a spontaneous mutation, even in people with no family history of the condition.

Hemophilia and genetics

Genetics plays a role in all three types of hemophilia. Both types A and B occur due to a mutation on the X chromosome, while type C affects other areas of the genetic code. Here is how it breaks down.

Types A and B

Both hemophilia A and hemophilia B involve a recessive mutation on the X chromosome. Biological males typically have an X and Y chromosome, while biological females typically have two X chromosomes.

This means that biological females will not likely inherit the disorder, since they will almost always have at least one non-mutated X chromosome. Instead, they can become carriers if they acquire one copy of the mutated X chromosome.

Being a carrier means that the person will not show any signs or symptoms of the condition, but they can still pass it on to their children.

For example, biological males can inherit hemophilia if their mother is a carrier and they get the mutated X gene from them.

Here are the odds of passing hemophilia on to a child and how it breaks down by gender:

Sex assigned at birthStatusOdds
Femalecarrier1 in 4
Femalenot a carrier1 in 4
Malewith hemophilia A/B1 in 4
Malewithout hemophilia A/B1 in 4

About two-thirds of all hemophilia A and B cases are passed down from parents to children. The rest can occur due to spontaneous mutation of the gene.

Type C

Like hemophilia A and B, hemophilia C is an inherited condition from a recessive gene. This type can affect males and females equally.

Hemophilia is diagnosed through a blood test. Your doctor will remove a small sample of blood from your vein and measure the amount of clotting factor present.

The sample is then graded to determine the severity of the factor deficiency and the severity of the condition.

Hemophilia A severity levels include:

  • Mild: occurs when factor levels are between 6 and 30 percent (about 25 percent of all cases)
  • Moderate: occurs when factor levels are between 1 and 5 percent (about 15 percent of all cases)
  • Severe: occurs when factor levels are less than 1 percent (about 60 percent of all cases)

Hemophilia B severity levels include:

  • Mild: occurs when factor levels are between 6 and 49 percent
  • Moderate: occurs when factor levels are between 1 and 5 percent
  • Severe: occurs when factor levels are less than 1 percent

Treatment for hemophilia can vary based on the type of hemophilia you have. The main goal of treatment is to replace the clotting factors so a person can form clots and prevent bleeding.

A doctor may prescribe the following based on the type of hemophilia you have:

  • Concentrated FVIII or FIX product. Often called clotting factor, these infused medications are used to treat types A and B, respectively. The medication can either be synthetic or made from human plasma. Often doctors prescribe them as part of an ongoing, regular treatment regimen known as prophylaxis.
  • Aminocaproic acid. This medication helps prevent the breakdown of blood clots. Doctors may prescribe this medication prior to a dental or other procedure.
  • Non-factor replacement therapies. These medications are a newer form of therapy that uses synthetic proteins to replicate the clotting factors. A doctor injects the medication into the skin. Examples of this therapy include emicizumab and desmopressin acetate.
  • Physical therapy. In more severe cases, you may need to go to physical therapy for rehabilitation if hemophilia has damaged your joints.
  • Pain management. If you have pain associated with the condition, your doctor may prescribe or recommend pain medications to help alleviate the pain.
  • New therapies. Scientists are looking at new forms of therapy, including gene therapies and the use of monoclonal antibodies.

Risk factors for inheriting hemophilia

Hemophilia A and B are more common in people assigned male at birth than people assigned female because the genetic transmission occurs due to a recessive gene on the X chromosome.

Hemophilia C is an autosomal inherited form of the disease, meaning that it affects biological males and biological females equally. This is because the genetic defect that causes this type of hemophilia isn’t related to sex chromosomes. In the United States, hemophilia C affects about 1 in 100,000 people.

Hemophilia is a condition that’s typically passed from parent to child. When someone is pregnant, there’s no way of knowing whether the baby has the condition.

However, if your eggs are fertilized in a clinic using in vitro fertilization, they can be tested for the condition. Then, only the eggs without hemophilia can be implanted.

If you’re worried your baby may develop hemophilia, pre-conception and prenatal counseling can help you understand your risk of passing hemophilia on to your baby.

The complications of hemophilia can include:

  • joint damage from repetitive bleeding
  • deep internal bleeding
  • fractures
  • neurological symptoms from bleeding within the brain

You’re also at an increased risk of developing infections, such as hepatitis, when you receive donor blood.

The following symptoms indicate a medical emergency. You should get treatment right away for any of these symptoms:

  • a severe headache
  • vomiting repeatedly
  • neck pain
  • blurred or double vision
  • extreme sleepiness
  • continuous bleeding from an injury

If you’re pregnant, it’s important that you see a doctor if you experience any of the above symptoms.

If you‘re experiencing a medical emergency, you should seek emergency medical care through a local hospital. For follow-up care and condition management, you can connect with a primary care doctor in your area using the Healthline FindCare tool.

Hemophilia is a blood condition associated with heavy bleeding. There are three types of hemophilia: A, B, and C. They differ in what clotting factors are affected.

The severity level of hemophilia can affect symptoms and their severity.

Treatment focuses on replacing clotting factors to prevent future issues with bleeding. A doctor may also recommend additional therapies as needed.

Can females have hemophilia?

Hemophilia A and B primarily affects biological males. This is because these types of hemophilia result from a recessive mutation on the X chromosome. Females often have at least one healthy X chromosome, which means they will likely only become a carrier unless both parents pass on a recessive X chromosome.

Hemophilia C can affect both males and females equally because it is not associated with the X or Y chromosome.

Can hemophilia go away?

Though treatment can help improve and prevent symptoms, there is currently no cure for hemophilia. You will need regular treatment to ensure your blood clots normally.

How common is hemophilia?

According to the CDC, hemophilia occurs in 1 out of every 5,000 male births. While it primarily affects biological males, it can affect all races and ethnic groups. Also, hemophilia A is about four times as common as B. About half of all people living with type A hemophilia have the severe form.