Can Females Get Hemophilia A? Causes and Symptoms Explained

Yes, females can and do get Hemophilia A. For a long time, women and girls with a pathogenic F8 variant (the genetic change that causes Hemophilia A) were often described only as “carriers.” This led to the dangerous misconception that they would never experience bleeding symptoms themselves.

Today, clinical guidelines recognize that females with low levels of Factor VIII—a crucial protein that helps your blood clot—have mild, moderate, or severe hemophilia, just like males ^[1]. Furthermore, even females with normal or near-normal Factor VIII levels can experience abnormal bleeding; these individuals are now classified as “symptomatic carriers” ^[1].

Why Does This Happen? Understanding X-Chromosome Inactivation

Hemophilia A is an X-linked condition, meaning the genetic instructions for making Factor VIII are located on the X chromosome. Males typically have one X and one Y chromosome. Because they only have one X chromosome, inheriting the F8 variant means they will have hemophilia.

Females typically have two X chromosomes. To prevent a toxic double-dose of X-chromosome genes, female cells go through a normal process in early development called lyonization or X-chromosome inactivation ^[2]. In every cell, one X chromosome is randomly “turned off.”

Ideally, about half of the cells turn off the X chromosome with the F8 variant, and half turn off the normal one. However, this process does not always split evenly. If a larger percentage of your cells turn off the normal gene—a phenomenon called skewed X-inactivation—your body will produce less Factor VIII, which can lead to hemophilia symptoms ^[2].

While skewed X-inactivation is a major contributor to lower Factor VIII, levels also naturally fluctuate due to age, hormones, pregnancy, and other biological factors. In rare cases, females can also inherit an F8 variant from both parents, or they may have a condition like Turner syndrome (where a female is born with only one X chromosome) ^[3][4].

Understanding Your Factor VIII Levels

Doctors measure how much active Factor VIII protein is in your blood. Levels are usually shown as a percentage (%) or in International Units per milliliter (IU/mL). Based on your levels, your care team may classify your condition as ^[1]:

• Mild Hemophilia A: 5% to just under 40% (0.05 to < 0.40 IU/mL)
• Moderate Hemophilia A: 1% to 5% (0.01 to 0.05 IU/mL)
• Severe Hemophilia A: Less than 1% (< 0.01 IU/mL)
• Symptomatic Carrier: 40% or higher (≥ 0.40 IU/mL), but with a personal history of abnormal bleeding.

Symptoms and Bleeding Risks

A single Factor VIII test result does not completely predict your bleeding risk. A “normal” laboratory result does not guarantee that you won’t experience symptoms. In one study of confirmed female carriers, 55% experienced abnormal bleeding, even though only 19% had Factor VIII levels below the 40% threshold used for a formal hemophilia diagnosis in that study ^[5].

Females with the F8 variant often experience ^[6][7][8]:

• Heavy Menstrual Bleeding: Periods lasting more than 7 days, soaking through a pad or tampon rapidly, or passing large blood clots. Over time, this can lead to iron-deficiency anemia.
• Easy Bruising and Nosebleeds: Frequent, unexplained bruising and nosebleeds that take a long time to stop.
• Medical and Dental Bleeding: Prolonged bleeding after having a tooth pulled, undergoing surgery, or delivering a baby.
• Joint and Muscle Bleeding: Swelling or pain in joints (like knees or ankles) or muscles, though this is less common than in males with severe hemophilia.

Urgent Care Warning: Seek emergency medical care and inform emergency staff of your F8 variant status immediately if you experience: bleeding that will not stop with firm pressure, a significant head injury, a sudden severe headache, blood in your urine or stool, or a rapidly enlarging, painful joint or muscle swelling. Do not wait for a routine appointment.

Surgery, Dental Work, and Childbirth

If you have an F8 variant, you need advance planning before any major medical procedure.

• Surgery and Dental Work: Do not assume you are safe from bleeding complications just because you were labeled a “carrier” in the past. Notify your surgeon, dentist, anesthetist, and Hemophilia Treatment Center (HTC) well in advance to create a written procedure plan that details your monitoring and treatment needs ^[9].
• Pregnancy and Childbirth: Pregnancy naturally increases Factor VIII levels for many women, but levels must be checked both during pregnancy and near delivery ^[10]. Adequate, documented Factor VIII levels are required before you can safely receive an epidural or spinal block for pain relief ^[10]. Furthermore, Factor VIII levels can drop rapidly after delivery, leading to postpartum hemorrhage (excessive or delayed bleeding after childbirth). Postpartum bleeding is a clinically significant risk, and a plan for continued monitoring after you give birth is essential ^[11].
• Newborn Safety: Care teams must also plan for the safety of the newborn, who may have inherited the hemophilia variant. To prevent head trauma, interventions like forceps, vacuum extraction, or fetal scalp monitoring are generally avoided if the baby’s genetic status is affected or unknown ^[10][12].

Treatment Options

Depending on your Factor VIII levels and your clinical history, a specialized hematology team can help you build a personalized management plan. Treatments may include ^[13]:

• Hormonal treatments (such as birth control pills or intrauterine devices) to manage heavy menstrual bleeding.
• Antifibrinolytics (like tranexamic acid) to help prevent blood clots from breaking down quickly during dental work or menstruation.
• Desmopressin (DDAVP), a medication that temporarily boosts Factor VIII levels. This requires a specialist assessment (a “DDAVP trial”) to confirm whether your body responds to it.
• Factor VIII concentrates (replacement therapy) to prevent or treat severe bleeding, joint disease, or surgical complications.

Safety Note: Never start nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, naproxen, or aspirin for menstrual cramps or joint pain without asking your hemophilia clinician, as these medications interfere with blood clotting and can worsen bleeding.