Rare within rare: women with haemophilia

Haemophilia, a serious, inherited bleeding disorder, is rare in men – but it’s even more rare in women, where the condition is underrecognised and overlooked.¹ Learn more about this gap in haemophilia care, and how it can be filled.

It’s estimated that over 6.9 million men and women have a bleeding disorder worldwide, including haemophilia, von Willebrand disease and other rare factor deficiencies.² For many years, it was believed that only men could have haemophilia, while women could only be ‘carriers’. But we now know women are also affected – the best estimates of the prevalence of haemophilia in women, based on the data available and world population estimate, indicate that the expected number of women with haemophilia worldwide is 359,000 (diagnosed and undiagnosed).²

Because of its rarity and a general lack of awareness, many women with haemophilia don’t seek medical advice, or are misdiagnosed, meaning they live with their symptoms for years, without even suspecting they have a bleeding disorder.

Haemophilia is caused by a coagulation (clotting) factor deficiency in the blood, due to a problem in one of the genes needed to form blood clots.³

In men (who inherit a single X chromosome from their mother), one altered copy of the gene is sufficient to cause haemophilia.

In women (who inherit two X chromosomes – one from each parent), one affected gene can mean that they develop moderate or mild haemophilia and can also experience mild to severe symptoms of the disorder, in the same way that men can. Women can also pass the affected gene on to their children. In extremely rare cases, women may inherit two affected X chromosomes from their parents, or one affected and one missing or non-functioning gene. However, very few cases of this have been reported in literature.⁴, 

Women with one or more affected genes can experience mild, moderate, or severe symptoms of haemophilia in the same way as men do, depending on the level of clotting factor in the blood:²,,

  • Joint damage: bleeding into joints which can cause damage over time

  • Excessive nosebleeds: frequent nosebleeds that last longer than 10 minutes

  • Easy bruising: regular new bruises that may be raised and larger than one inch wide

  • Heavy bleeding: following dental or other surgery, or bleeding from cuts lasting longer than five minutes

In addition to the above, women with bleeding disorders such as haemophilia often experience heavy menstrual periods (menorrhagia).⁸ This can be difficult to define, because what some girls and women identify as 'heavy' can vary, but signs include: ⁷

  • Bleeding for more than seven days

  • Passing clots that are bigger in size than a bottle cap

  • Needing to change a tampon and/or pad every two hours or less

If you, or someone you know is experiencing one or more of these symptoms, talk to your doctor or healthcare professional.

How haemophilia impacts women

Anaemia: Excessive or prolonged menstrual bleeding can cause anaemia (low red blood cell count/low blood iron levels), with symptoms of fatigue, paleness, lack of energy and shortness of breath.⁹

Physical, social and emotional quality of life: Women and girls living with heavy menstrual periods might also take time off work and school, isolate themselves from family and friends, or avoid social or sporting events due to pain, fatigue, discomfort or the fear of staining clothing.⁹

Family planning: Many women with haemophilia also experience guilt because of the fear of passing on a bleeding disorder or having a daughter who must in turn face this possibility.¹⁰

During pregnancy: Mothers who carry the haemophilia gene are at risk of serious bleeding after delivery. Some women have long-lasting bleeding from the birth canal called postpartum haemorrhage and can require treatment to stop the bleeding.¹¹

In general, women have been routinely excluded from many clinical trials, due to possible interactions of test treatments with fluctuating hormones, complexities with the menstrual cycle and concerns of potentially damaging unborn foetuses.¹² In some cases, studies have only included women at the early stages of the menstrual cycle, when hormones are lower and more equivalent to those in men.¹² This means we have little understanding of how differing hormone levels affect treatment performance and studies do not reflect the real world. This is known as selection bias: eligible participants are excluded or omitted from clinical trials generating results that differ from what would have been observed had women been included.¹³ In fact, 80% of treatment withdrawals from the market are due to unanticipated gender-prescribing trends or unacceptable side effects observed in women, highlighting the importance of including women in clinical trials.¹⁴

Because haemophilia is poorly recognised in women, few studies have included them. Clinical studies evaluating existing and new haemophilia treatment options in women are crucial to provide women with access to the innovative treatments that offer the benefits and improvements in quality of care offered to men.

Roche is committed to working with the haemophilia community to close this gap in haemophilia care by raising awareness that women can have haemophilia too.

Roche is also actively enrolling women in clinical trials for new and existing treatments for haemophilia A. In addition, our trials include health indicators that are unique to women with bleeding disorders, with the aim to optimise care.²

It’s important to provide more support to address the specific symptoms that women with haemophilia experience, and to ensure these are not overlooked in the development of care plans. Consideration should be given to: 

  • Raising awareness of the symptoms and impact of haemophilia on women, especially among those who are at risk

  • Increase genetic screening to support with the identification of individuals impacted by haemophilia

  • Support with treatment decision-making and symptom management, especially for those that only impact women, such as heavy menstrual bleeding

  • Preconception counselling to discuss genetic diagnosis and the risk of passing on an affected gene

  • Guidance on the maternal bleeding risks during conception, delivery, and the post‐partum period

By working together, we can ensure that women are recognised as a small but important part of the bleeding disorders community, deserving of considered care and our support in managing haemophilia, von Willebrand disease and other rare factor deficiencies.


  1. Weyand AC, James PD. Sexism in the management of bleeding disorders. Res Pract Thromb Haemost. 2020;5(1):51-54. 

  2. Skinner MW. WFH: Closing the global gap – achieving optimal care. Haemophilia. 2012;18: 1-12.

  3. Centers for Disease Control and Prevention. Women Can Have Hemophilia, Too [Internet; cited 2022 March]. Available from:

  4. d'Oiron R, O'Brien S, James AH. Women and girls with haemophilia: Lessons learned. Haemophilia. 2021; 27( suppl. 3): 75– 81.  

  5. Miller CH, Bean CJ. Genetic causes of haemophilia in women and girls. Haemophilia. 2021;27(2):e164-e179. 

  6. Nationwide Children’s. Hemophilia Carrier [Internet; cited 2022 March]. Available from:

  7. National Hemophilia Foundation. Women and Bleeding Disorders [Internet; cited 2022 March]. Available from:

  8. The Haemophilia Society. Women with Bleeding Disorders [Internet; cited 2022 March]. Available from:

  9. Centers for Disease Control and Prevention. Bleeding Disorders in Women [Internet; cited 2022 March]. Available from:

  10. Cassis F. Psychosocial Care For People With Hemophilia. Treatment Of Hemophilia. 2007; 44. 

  11. Centers for Disease Control and Prevention. Hemophilia [Internet; cited 2022 March]. Available from:

  12. Bruinvels G, Burden RJ, McGregor AJ, et al. Sport, exercise and the menstrual cycle: where is the research? British Journal of Sports Medicine 2017;51:487-488.

  13. Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.2 (updated February 2021). Cochrane, 2021. Available from

  14. Rademker M. Do women have more adverse drug reactions? Am J Clin Dermatol 2001;2(6):349-51.

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