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PubMed This is a summary of 17 peer-reviewed journal articles Updated
Hematology

Understanding Hemophilia: The Basics & Your Diagnosis

At a Glance

Hemophilia is a genetic bleeding disorder caused by low levels of clotting factors VIII or IX. Modern care relies on prophylaxis—regular preventative treatments that stop bleeds before they happen—allowing most patients to live full, active lives with a normal life expectancy.

Receiving a diagnosis of hemophilia can feel overwhelming, but it is important to know that you are entering a community with a long history of advocacy and a future filled with advanced medical options. Whether you are an adult patient or a parent orienting your family, this guide is here to support you. While hemophilia was once a condition that severely limited a person’s life, modern medicine has transformed it into a manageable chronic condition. Today, many people with hemophilia live full, active lives and reach the same life expectancy as those without the condition [1][2].

What is Hemophilia?

Hemophilia is a genetic bleeding disorder where the blood does not clot properly. This happens because the body is missing or has very low levels of certain proteins called clotting factors, which act like “glue” to help stop bleeding [3][4].

There are two primary types of hemophilia, distinguished by which specific protein is missing:

  • Hemophilia A (Classic Hemophilia): The person is missing or has low levels of Factor VIII (Factor 8). It is the more common form, occurring in approximately 24.6 out of every 100,000 male births [5][3].
  • Hemophilia B (Christmas Disease): The person is missing or has low levels of Factor IX (Factor 9). This form is less common, occurring in approximately 5.0 out of every 100,000 male births [5][6].

Both types are X-linked recessive conditions, meaning they primarily affect males, while females are usually “carriers” who may or may not have mild bleeding symptoms themselves [3][7].

Three Stabilizing Truths for Your Journey

As you process this diagnosis, keep these three facts in mind to help orient your family:

  1. Prevention is the Modern Standard: In the past, treatment only happened after a bleed started. Today, the standard of care is prophylaxis—regularly scheduled treatment designed to prevent bleeds from ever happening [2][8]. This approach helps protect joints and allows for a much more active lifestyle.
  2. You Are Not Alone in This: Most patients in the U.S. receive care at Hemophilia Treatment Centers (HTCs). These are specialized clinics where a multidisciplinary team—including hematologists, specialized nurses, physical therapists, and social workers—works together to support every aspect of your health, including emotional and social well-being [9][10].
  3. Treatment is Advancing Rapidly: We are currently in an era of “novel therapies.” Beyond traditional infusions, there are now “non-factor” treatments that can be given as a simple injection under the skin (subcutaneous), as well as groundbreaking gene therapies that may allow the body to produce its own clotting factor for years at a time [2][11][12].

Understanding Severity

Your doctor will determine the “severity” of the hemophilia based on the level of factor activity in the blood:

  • Severe: Less than 1% factor activity. Bleeding can happen spontaneously (without a clear injury), often into muscles or joints [13][14].
  • Moderate: 1% to 5% factor activity. Bleeding usually follows a minor injury.
  • Mild: 5% to 40% factor activity. Bleeding usually only occurs after a major injury or surgery [15].

Regardless of the severity, your care team will help you create a “bleeding plan” so you always know exactly what to do if an injury occurs [2][16]. It is also common for parents to feel a sense of guilt or anxiety following a genetic diagnosis; acknowledging these feelings is a vital part of building resilience for your family [17].

Common questions in this guide

What is the difference between Hemophilia A and Hemophilia B?
Hemophilia A means your body is missing or has low levels of clotting Factor VIII (8). Hemophilia B means you are missing or have low levels of Factor IX (9). Both types cause similar bleeding issues but require different treatments.
How is the severity of hemophilia determined?
Severity is based on the level of clotting factor activity in your blood. It is classified as severe if factor activity is less than 1%, moderate if it is between 1% and 5%, and mild if it is between 5% and 40%.
What does prophylaxis mean for hemophilia treatment?
Prophylaxis is a preventative treatment approach where patients receive regular medication to stop bleeds before they start. This protects your joints from damage and allows you to live a much more active lifestyle.
Can people with hemophilia live a normal lifespan?
Yes. Thanks to modern medical advancements like preventative therapies, many people living with hemophilia today can reach the same life expectancy as those without the condition.
What is a Hemophilia Treatment Center (HTC)?
An HTC is a specialized clinic that provides comprehensive care for bleeding disorders. The team usually includes hematologists, nurses, physical therapists, and social workers who coordinate all aspects of your medical and emotional well-being.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What is my (or my child's) specific factor activity level, and how does that define the severity of the hemophilia?
  2. 2.How does our local Hemophilia Treatment Center (HTC) coordinate care between different specialists like hematologists, physical therapists, and social workers?
  3. 3.What is the specific 'bleeding plan' for emergencies, and which hospital should we go to if an injury occurs after hours?
  4. 4.When should we begin 'prophylaxis' (preventative treatment), and what are the pros and cons of the different types of therapy available today?
  5. 5.How can we get tested for 'inhibitors,' and what does that mean for our long-term treatment plan?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (17)
  1. 1

    All-cause mortality and causes of death in persons with haemophilia: A systematic review and meta-analysis.

    Alam AU, Karkhaneh M, Attia T, et al.

    Haemophilia : the official journal of the World Federation of Hemophilia 2021; (27(6)):897-910 doi:10.1111/hae.14423.

    PMID: 34592037
  2. 2

    Nothing short of a revolution: Novel extended half-life factor VIII replacement products and non-replacement agents reshape the treatment landscape in hemophilia A.

    Abdelgawad HAH, Foster R, Otto M

    Blood reviews 2024; (64()):101164 doi:10.1016/j.blre.2023.101164.

    PMID: 38216442
  3. 3

    Practices and challenges for hemophilia management under resource constraints in Thailand.

    Moonla C, Sosothikul D, Pongtanakul B, et al.

    Orphanet journal of rare diseases 2023; (18(1)):110 doi:10.1186/s13023-023-02718-1.

    PMID: 37161533
  4. 4

    [Treatment of haemophilia: From replacement to gene therapy].

    Páramo JA

    Medicina clinica 2021; (157(12)):583-587 doi:10.1016/j.medcli.2021.04.031.

    PMID: 34509300
  5. 5

    Establishing the Prevalence and Prevalence at Birth of Hemophilia in Males: A Meta-analytic Approach Using National Registries.

    Iorio A, Stonebraker JS, Chambost H, et al.

    Annals of internal medicine 2019; (171(8)):540-546 doi:10.7326/M19-1208.

    PMID: 31499529
  6. 6

    Medical costs and hospital utilization for hemophilia A and B urban inpatients in China: a national cross-sectional study.

    Huang Z, Nicholas S, Yang Y, et al.

    BMC health services research 2022; (22(1)):230 doi:10.1186/s12913-022-07626-x.

    PMID: 35183186
  7. 7

    Protein-Engineered Coagulation Factors for Hemophilia Gene Therapy.

    Samelson-Jones BJ, Arruda VR

    Molecular therapy. Methods & clinical development 2019; (12()):184-201 doi:10.1016/j.omtm.2018.12.007.

    PMID: 30705923
  8. 8

    MG1113, a specific anti-tissue factor pathway inhibitor antibody, rebalances the coagulation system and promotes hemostasis in hemophilia.

    Kwak H, Lee S, Jo S, et al.

    Research and practice in thrombosis and haemostasis 2020; (4(8)):1301-1312 doi:10.1002/rth2.12438.

    PMID: 33313469
  9. 9

    Evidence-based guidelines support integrated disease management as the optimal model of haemophilia care.

    Pipe SW, Kessler CM

    Haemophilia : the official journal of the World Federation of Hemophilia 2016; (22 Suppl 3()):3-5 doi:10.1111/hae.12997.

    PMID: 27348395
  10. 10

    Updated Egyptian national guidelines for management of hemophilia A in children & adolescents.

    Mokhtar G, El-Beshlawy A, Alfy ME, et al.

    Annals of hematology 2025; (104(10)):5463-5473 doi:10.1007/s00277-025-06557-x.

    PMID: 41065813
  11. 11

    Gene Therapy with Fidanacogene Elaparvovec in Adults with Hemophilia B.

    Cuker A, Kavakli K, Frenzel L, et al.

    The New England journal of medicine 2024; (391(12)):1108-1118 doi:10.1056/NEJMoa2302982.

    PMID: 39321362
  12. 12

    Emicizumab prophylaxis in patients with haemophilia A with and without inhibitors.

    Ebbert PT, Xavier F, Seaman CD, Ragni MV

    Haemophilia : the official journal of the World Federation of Hemophilia 2020; (26(1)):41-46 doi:10.1111/hae.13877.

    PMID: 31746522
  13. 13

    Gene therapy for hemophilia: looking beyond factor expression.

    Yamaguti-Hayakawa GG, Ozelo MC

    Experimental biology and medicine (Maywood, N.J.) 2022; (247(24)):2223-2232 doi:10.1177/15353702221147565.

    PMID: 36691324
  14. 14

    Effect of Prophylactic Management of Hemophilia on Bleeding Episodes.

    Roy S, De AK

    Indian journal of hematology & blood transfusion : an official journal of Indian Society of Hematology and Blood Transfusion 2019; (35(3)):496-501 doi:10.1007/s12288-018-1054-6.

    PMID: 31388263
  15. 15

    Preferences and Health-Related Quality-of-Life Related to Disease and Treatment Features for Patients with Hemophilia A in a Canadian General Population Sample.

    Johnston K, Stoffman JM, Mickle AT, et al.

    Patient preference and adherence 2021; (15()):1407-1417 doi:10.2147/PPA.S316276.

    PMID: 34194224
  16. 16

    Journeying Towards Excellence in the Care of Patients with Haemophilia and Other Inherited Bleeding Disorders From a Developing World: Insights From Tanzania.

    Rwezaula SS, Mtoba SD, Gosse RA, et al.

    Journal of blood medicine 2025; (16()):413-423 doi:10.2147/JBM.S537383.

    PMID: 40955318
  17. 17

    Guilt in parents of children diagnosed with hemophilia: A qualitative study.

    Onel AE, Zengin D, Bal Yilmaz H

    Journal of pediatric nursing 2026; (86()):51-59 doi:10.1016/j.pedn.2025.10.032.

    PMID: 41207084

This page provides educational information about hemophilia and its diagnosis. Always consult a hematologist or your Hemophilia Treatment Center (HTC) for medical advice and personalized emergency bleeding plans.

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