Hemophilia in women

Last updated Jan. 11, 2024, by Susie Strachan
Fact-checked by Patricia Silva, PhD

Although hemophilia, a bleeding disorder that interferes with blood clotting, is more common in men, women can have it, too.

Hemophilia can lead to prolonged bleeding, often into the joints, or after surgery or an injury.

Among several hemophilia types, each is characterized by a deficiency of a specific clotting factor protein. The most common type is hemophilia A, which accounts for approximately 80% of cases. Hemophilia B accounts for the remaining 15% to 20%. Both types primarily affect boys and men.

Although uncommon, women can have hemophilia A or B, with symptoms similar to men. In most cases, however, women are carriers, meaning they can pass on a copy of the mutated gene that causes hemophilia to their children, even though they themselves may not experience disease symptoms.

Hemophilia C affects women at the same rate as men.

How can females have hemophilia?

The question “Is hemophilia more common in males or females?” is mainly based on genetics.

Most cases of hemophilia inheritance are caused by mutations in genes found on the X chromosome, one of the two sex-determining chromosomes.

Mutations in the F8 and F9 genes cause hemophilia A and B, respectively, and these two genes are located on the X chromosome. Girls have two X chromosomes and boys have one X chromosome and one Y chromosome.

Only one working copy of F8 or F9 is needed for the body to be able to make enough of the corresponding clotting factors. Women who have an F8 or F9 mutation on one X chromosome usually don’t develop hemophilia as long as there’s a functional version of the gene on their other X chromosome.

However, girls can have hemophilia A or B when they inherit two X chromosomes containing faulty copies of the F8 or F9 gene, or if they receive a faulty copy and the other one, although functional, is present in the X chromosome that becomes inactivated.

Hemophilia is usually thought of as a bleeding disorder that affects men — based on the pattern of hemophilia X-linked inheritance — but women can have unrecognized bleeding symptoms that make it harder to get a hemophilia diagnosis, or to evoke empathy from healthcare professionals and others after a diagnosis.

The F11 gene that causes hemophilia C is not located on the X chromosome, but is found on chromosome 4. Hemophilia C will only develop if both copies of the F11 gene are mutated.

While most types of hemophilia are genetic disorders caused by inherited mutations, acquired hemophilia develops later in life and is not passed down through families. It occurs equally in women and men.

Women with a family history of hemophilia should consult healthcare professionals about genetic counseling and testing to understand their risk and to learn best ways to manage the disease.

How does hemophilia affect women?

Hemophilia causes symptoms in women that can range from mild to severe, partly depending on the amount of clotting factor activity in their blood.

A 2021 study of women receiving care at hemophilia treatment centers in the U.S. showed that, while women with severe or moderate hemophilia are uncommon, nearly one in five patients with mild hemophilia are female.

A 2023 study found female hemophilia A patients and carriers have more frequent bleeding than male patients, yet a much smaller proportion receive replacement therapy to prevent or stop bleeding episodes. The study also noted women tend to be diagnosed only as carriers, even when their factor VIII levels are less than half of normal.

Hemophilia symptoms in females include heavy menstrual bleeding and heavy bleeding after giving birth. Heavy menstrual bleeding can lead to anemia, low iron levels, and fatigue.

Hemophilia isn’t the only reason someone may be experiencing heavy menstruation. Heavy periods can result from other health issues, such as fluctuating hormone levels, using certain intrauterine devices for birth control, cancer and other disorders, and certain medications.

Similar to men with hemophilia, women with the disorder may also experience hemophilia complications such as joint and muscle bleeding, and easy bruising.

With modern treatments, hemophilia doesn’t appear to reduce life expectancy significantly for women.

Does hemophilia affect pregnancy?

Pregnant women who are living with hemophilia or are carriers may have a higher risk of bleeding issues such as maternal bleeding, fetal bleeding, and excessive bleeding during delivery and postpartum.

A comprehensive care plan set up by hematologists and obstetricians is crucial to managing hemophilia risks during pregnancy. For bleeding prevention, it may be necessary to adjust the dosage of clotting factor replacement.

The care plan for hemophilia and pregnancy may include proper nutrition, access to support groups, and how the infant will be delivered. For example, if the unborn child is a male who could potentially be affected by hemophilia — increasing the risk of fetal bleeding — a caesarian section may be considered.

However, as Hemophilia News Today columnist Shellye Horowitz writes, both male and female infants should have equal protection prior to birth.

“It is less common, though sometimes encouraged, to test female children before birth to see if they have the mutated gene that causes hemophilia,” she writes in a column about keeping moms and babies safe. “Care should be taken during the birth of any baby who has the possibility of having a mutated hemophilia gene.”

Horowitz also emphasizes the need for a comprehensive treatment plan for women with hemophilia during pregnancy, delivery, and postpartum.

As she points out, “Bringing a new life into this world is a precious gift. Those first moments should be protected and full of joy.”

Hemophilia News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.