Haemophilia and carrying the gene

Can females have haemophilia?

Many girls or women who have the factor VIII (8) or IX (9) gene alteration causing haemophilia do not have symptoms of a bleeding disorder. If at least one of their X chromosomes has a factor VIII or IX gene that works, their body can usually produce normal or near normal levels of factor and they do not have bleeding problems.

In genetics any female who has this gene alteration is called a 'haemophilia carrrier'.

However, approximately 20-30% of girls and women who are carriers have reduced clotting factor levels and may have a bleeding tendency.

In the past women and girls with bleeding symptoms were generally described as 'symptomatic carriers'.

  • If their factor levels fall in the range for mild haemophilia (5 – 40% of normal clotting factor), they are now recognised as having mild haemophilia.
  • In very rare cases, some girls or women have particularly low factor levels causing them to have moderate or severe haemophilia.
  • Some females with factor levels at the lower end of normal (40-50%) may also experience abnormal bleeding. If further investigation shows that this bleeding is related to a factor VIII or IX deficiency, they will be treated as having haemophilia, but they will be described as a 'symptomatic haemophilia carrier'.

Factor level testing

All females who are carriers should have testing for their clotting factor levels. Ideally this should be done early in life so that females with low factor levels are identified and managed appropriately before they have problems with bleeding.

Unlike males with haemophilia, where the factor level is nearly always the same within the same family, the factor level in females who are carriers is unpredictable and varies between family members.

Women and girls with lower levels should have theirs checked periodically, as their factor levels may change with age, pregnancy and hormonal medications. If their factor level is low, they will need a treatment plan to prevent bleeding problems and manage any situations that occur, including medical and dental procedures and surgery.

It is important to remember that normal factor VIII or factor IX levels will not tell you whether you have the gene alteration causing haemophilia. Many females who carry the gene alteration have normal factor levels. Finding out your clotting factor level helps you and your Haemophilia Treatment Centre decide if you need to develop a treatment plan specifically for you. If your levels are normal a separate genetic test is needed to find out if you have the gene alteration.

Click here for more information on genetic testing

Read the booklets:

Shorter/simpler version
Haemophilia testing in women and girls a guide
A guide to haemophilia testing in women and girls (genetic testing and factor level testing)

More comprehensive version

Haemophilia testing in women and girls
Haemophilia testing in women and girls: your questions answered (genetic testing and factor level testing)

Download the fact sheets:
Haemophilia A and haemophilia B
Haemophilia in females (PDF, 1.1 MB)

Working with your HTC
Haemophilia treatment and care for young women (PDF 1.3 MB) 

Date last reviewed: April 2023

What are the symptoms of haemophilia in females?

Examples of having a bleeding tendency or symptoms in females may include:

  • Bruising easily
  • Having more painful swelling and bruising than you would expect after an injury, eg falling off a bike, car accident, sporting injury
  • Heavy and/or long periods. This is called heavy menstrual bleeding or sometimes abnormal uterine bleeding or menorrhagia. It can lead to low iron levels or anaemia
  • Bleeding or oozing for a long time after dental surgery or extractions, other surgery and medical procedures, injuries or accidents
  • Heavy bleeding for extended time after childbirth (particularly with delayed or late postpartum haemorrhage)
  • Females with very low clotting factor levels may also have internal bleeding into joints, muscles, organs and soft tissues.

Heavy menstrual bleeding

Heavy periods or heavy menstrual bleeding can be difficult to define because what different girls and women call 'heavy' can vary. Doctors may also use the terms 'abnormal uterine bleeding' or 'menorrhagia'. These are some signs that menstrual bleeding is 'heavier' than average: 

  • Soaking through a tampon and pad around two hourly, or needing to change during the night
  • Periods that last longer than 8 days
  • Bleeding with clots bigger than a 50 cent piece in size.

Heavy menstrual bleeding can lead to anaemia (low red blood cell count/low blood iron levels), with symptoms of fatigue, paleness, lack of energy and shortness of breath.

Although these can be symptoms related to haemophilia, they can also be symptoms of a gynaecological disorder, so it is important to consult a gynaecologist.

With diagnosis and appropriate treatment, these bleeding problems can usually be reduced or managed.

Care and management

If you are a woman or girl with a bleeding disorder, a holistic or comprehensive care approach to your health care can help you to achieve better health and quality of life. Specialist gynaecological care over your lifetime is important to manage any gynaecological issues that occur. These may not be related to haemophilia, but in some cases the bleeding disorder may make the bleeding problems worse.

At times in their life, some symptomatic women may need to have gynaecological surgery or procedures. If this happens, it is important that this is managed in a team, with discussion between the woman, the Haemophilia Centre and the gynaecologist and/or surgeon.

Ideally your medical care team should work together on your health care and should include:

  • A gynaecologist
  • A haematologist specialising in bleeding disorders
  • A GP
  • A paediatrician or obstetrician, if relevant at the time.

Click here for more information on treatment for haemophilia

Read our booklets for more information on bleeding symptoms, factor level testing and a treatment plan:

Shorter/simpler version

Haemophilia testing in women and girls a guide
A guide to haemophilia testing in women and girls (genetic testing and factor level testing)

More comprehensive version

Haemophilia testing in women and girls
Haemophilia testing in women and girls: your questions answered

Download the fact sheets:
Haemophilia A and haemophilia B
Haemophilia in females (PDF, 1.1 MB)

Women's bleeding explained
Women's bleeding explained (PDF, 2.1 MB)

Working with your HTC
Haemophilia treatment and care for young women (PDF 1.3 MB) 

Date last reviewed: April 2023

Why do women and girls have genetic testing for haemophilia?

A normal factor VIII or factor IX level test will not tell women or girls whether they carry the  gene alteration causing haemophilia. Some women or girls may have normal factor levels, but still carry the gene alteration.

In genetics, all females who have the gene alteration causing haemophilia are called 'carriers'.

A common time for testing whether a girl or woman is a carrier is when she reaches childbearing age and can understand the process and implications fully and make the decision for herself. Finding out whether she has the gene alteration is a process which will take time, sometimes many months. This may involve:

  • Discussion with a haemophilia specialist and/or genetic counsellor
  • Information and education about haemophilia, treatment and inheritance
  • Weighing up the pros and cons of genetic testing with advice and support from specialists, counsellors and other experts - for example, the role of genetic testing in understanding her bleeding disorder; its effect on her perception of herself and on her relationships; her personal understanding of what it’s like to have haemophilia; the impact on children and other family members; her personal religious and cultural beliefs; future disclosure obligations and implications for life or income protection insurance; any costs involved; and other issues relevant to her personal situation
  • Looking at the family tree to identify other family members who may have the gene alteration
  • Blood tests for other affected family members (eg, a man with haemophilia) to identify the particular genetic mutation causing haemophilia in her family
  • A simple blood test for the woman or girl to see if she has the same family genetic mutation
  • Genetic analysis in a laboratory. This can take longer if the family mutation is not known - sometimes months.

Many people find that undertaking these tests gives them a lot to think about. The Haemophilia Treatment Centre can help with information and advice about genetic testing and can provide a referral to a genetic counsellor, if needed. Women, their partner, parents or family can talk to the Haemophilia Treatment Centre or genetic counsellor individually or together prior to testing and many find it helpful.

Where can I have a genetic test?

Usually your state or territory clinical genetics service or your Haemophilia Treatment Centre (HTC) will undertake your genetic testing. They can also provide genetic counselling

They will use a specialist laboratory to analyse the results. You will need a referral. 

If you are speaking to your general practitioner (GP) about genetic testing, ask them to refer you to an HTC for diagnosis. If your GP is reluctant to refer you for genetic testing, you can request a referral to a clinical genetics service to discuss your options.

What if I change my mind?

If a person starts exploring genetic testing but decides against it, there is no obligation to complete the process.

For more information about genetic testing, see the Policies and Position Statements on the Human Genetics Society of Australasia web site

For more information about testing for haemophilia before birth, read the section in Pregnancy.

For more information about genetic testing for haemophilia, read our booklets:

Shorter/simpler version
Haemophilia testing in women and girls a guide
A guide to haemophilia testing in women and girls (genetic testing and factor level testing)

More comprehensive version

Haemophilia testing in women and girls
Haemophilia testing in women and girls: your questions answered

Finding out you carry the gene
Read more about the experiences of women in our Finding out you carry the gene booklet 

Date last reviewed: April 2023

How do I plan a family with haemophilia?

For people with haemophilia or women who carry the gene, planning a family can raise a number of questions:

  • Will their children have haemophilia or carry the gene?
  • If so, how will this affect them?
  • How can they find out?
  • What are the options for planning a family?
  • How can a mother who carries the gene plan for a safe pregnancy and delivery?
  • Who will help with all of this?

Haemophilia Centres can help with questions about having children. It may be helpful to review the information about how haemophilia is passed on to children here.

Often people have a particular view of haemophilia based on their memories of their brother, father or grandfather’s experience. Treatment for haemophilia has improved a great deal over the years and it can be valuable to learn more about how haemophilia is treated now and to speak to other people with haemophilia or parents of children with haemophilia or the Haemophilia Centre to see how things have changed. The Haemophilia Centre can also give a referral to a genetic counselling service that specialises in bleeding disorders.

Date last reviewed: July 2013

How do I prepare for pregnancy?

With good management, women who carry the haemophilia gene have no more problems with delivering a healthy baby than other mothers. However, it is very important to plan and prepare as much as possible.

This involves:

  • Ideally, if planning a pregnancy, discussing this with a haemophilia specialist who may refer to a genetic counsellor
  • When the pregnancy is confirmed, contacting the Haemophilia Centre for advice on local obstetric services with experience of haemophilia
  • Asking the haemophilia and obstetrics teams to consult with each other to plan for a smooth and safe pregnancy and delivery and care for the newborn
  • Checking with the Haemophilia Centre before having any invasive procedures, such as chorionic villus sampling or amniocentesis
  • Discussing suitable choices for anaesthesia, especially an epidural, with the Haemophilia Centre and obstetrics teams.

A normal vaginal delivery is usually recommended unless there are obstetric complications.

Identifying the sex of the baby

If a pregnant woman knows she carries the altered gene causing haemophilia, it is advisable to determine the sex of the baby before birth, preferably with a non-invasive test with minimal risk to the foetus, such as ultrasound. A male baby is more likely to be affected by haemophilia than a female. The woman and her partner can choose if they want to be told the sex of the baby or not before delivery even if the haemophilia and obstetric teams are aware. If neither the couple nor the medical staff know the sex of the baby and no other genetic testing of the foetus has been carried out, the pregnancy and birth will be managed as if the baby is a male with haemophilia to ensure the baby is delivered safely.

Testing for haemophilia before birth

For a woman or couples who wish to test for haemophilia before birth, there are two main testing options:

  • Prenatal diagnostic testing: a test during the pregnancy to check the sex of the baby. If it is male, further testing can check for the family gene mutation or alteration, which will show if the baby has haemophilia
  • IVF with pre-implantation genetic diagnosis (PGD): using IVF technology to test embryos for the family gene alteration, before embryo implantation and pregnancy.

For these options to be available the gene alteration in the family must be known.

A genetic counsellor can explore these reproductive options with the woman or the couple in further detail, along with any implications. There may also be substantial costs involved for these tests and procedures and it may be valuable to clarify this and options for support beforehand.

If a pregnant woman has a history of haemophilia in the family and does not know whether she carries the gene, it is important to let the obstetrics team know so that they can plan a safe delivery of the baby with the haemophilia team.

Date last reviewed: July 2013

What tips do others have?

  • Stay in regular contact with your local Haemophilia Treatment Centre (HTC) team and make sure you keep up with anything new. The HTC is there to help and can give you advice or talk over any problems or concerns
  • Keep in touch with your Haemophilia Foundation for updates on new information and enjoy a chat with other women who know what it’s like.
  • Let your dentist or your doctor know you have a bleeding disorder and advise your HTC team in advance of planned medical or dental procedures, no matter how minor, so that any procedures such as surgery, biopsies, childbirth, gynaecological or dental procedures that may result in bleeds can be managed in liaison with your HTC team
  • Consult with your haematologist before taking medicines containing aspirin, non-steroidal anti-inflammatory drugs, and other blood thinners or supplements, herbal or homeopathic medicines that affect platelet function or clotting. This includes fish oil capsules with omega-3 fatty acids, and herbal treatment doses of ginkgo biloba, ginger, ginseng and chondroitin
  • Ask your HTC for an ABDR patient card with your diagnosis, recommended treatment and who to contact in an emergency. Keep it on hand and show it to your other doctors or dentist and ask them to liaise with the HTC team.

Date last reviewed: September 2020
Adapted From:

Haemophilia. Rev. edn. Melbourne: HFA, 2013 2MB

Living with mild haemophilia: a guide. Melbourne: HFA, 2011 2.95MB


Australian Bleeding Disorders Registry. Annual Report 2020-21. Canberra: National Blood Authority, 2021. [PDF, 1.7MB]

Australian Haemophilia Centre Directors' Organisation. Guidelines for the management of haemophilia in Australia. Canberra: National Blood Authority, 2016.

Hermans C, Kulkarni R. Women with bleeding disorders. Haemophilia. 2018;24(Suppl. 6):29-36.

World Federation of Hemophilia. Guidelines for the management of hemophilia. 3rd edn. Haemophilia 2020; 26(Suppl. 6): 1-158.


Some sections in this publication were originally published by the World Federation of Hemophilia (WFH) and the Canadian Hemophilia Society (CHS) and have been adapted with permission. The WFH and CHS are not responsible for any inaccuracies in content different from the content of the original English editions.


Many thanks to the HFA Women with Bleeding Disorders Consumer Review Panel and the Mild Haemophilia Health Professional Review Panel for their suggestions on topics and content to include.

This booklet was reviewed by Leonie Mudge and Kate Lenthen from Australia/New Zealand Haemophilia Social Workers’ and Counsellors’ Group; Anne Jackson, Penny McCarthy, Megan Walsh and Claire Bell from Australian Haemophilia Nurses’ Group; Ian d’Young, Abi Polus and Wendy Poulsen from Australian and New Zealand Physiotherapy Haemophilia Group; Katherine Rose, Senior Genetic Counsellor, Monash Medical Centre, Victoria; Dr Chris Barnes, Dr Simon Brown, Dr Simon McRae and Dr John Rowell from Australian Haemophilia Centre Directors’ Organisation; and bleeding disorder community representatives from HFA Haemophilia and Women’s Project Consumer Review Groups.

Inheritance and information about women was reviewed by Dr Julie Curtin, Dr Jane Mason and Dr Stephanie P'ng from Australian Haemophilia Centre Directors’ Organisation in October 2018.

Date last reviewed: March 2023

Important Note: This information was developed by Haemophilia Foundation Australia for education and information purposes only and does not replace advice from a treating health professional. Always see your health care provider for assessment and advice about your individual health before taking action or relying on published information.
This information may be printed or photocopied for educational purposes.