Factor XI Deficiency

Posted On: April 7, 2022 By Nathan D. Fox, MD

Among the many genetic conditions that can affect your pregnancy, factor XI (11) deficiency is one that could potentially affect your blood, causing abnormal bleeding, that could impact childbirth.

What is Factor XI Deficiency?

In the simplest sense, factor XI deficiency potentially makes it harder to stop the flow of blood following medical procedures or injuries. It is also known as hemophilia C. Factor XI is a clotting factor of your blood, meaning it helps prevent excessive bleeding when you are injured or undergo surgery. A deficiency of this clotting factor can occur in both men and women due to a genetic mutation in the genes that code for it. This disorder is often recessive, meaning a person would need two mutated copies of the gene to experience factor XI deficiency, although in some cases even a single gene can cause mildly abnormal bleeding, and in some lineages the disorder is dominant.

Factor XI deficiency is a rare disorder that can affect anyone, but is much more common in the Ashkenazi Jewish population (up to 10% are heterozygous, or have one mutated copy of the factor XI gene).

Normal levels of factor XI in your body fall somewhere between 70% and 150%. Because this disorder causes variable deficiencies in factor XI, people can be mildly or severely deficient. Mild to moderate deficiency (heterozygous, one mutated copy) results in factor XI levels between 20% and 70% whereas severe deficiency (homozygous, two mutated copies) results in levels under 15%, and often under 5%.

How Does Factor XI Deficiency Affect Pregnancy?

In women, factor XI deficiency may increase the risk for post-partum hemorrhage (PPH), but fortunately it usually does not. Factor XI deficiency may also impact the safety of regional anesthesia (epidural or spinal), so we may recommend consultation with a hematologist or OB anesthesiologist (or both) prior to delivery, based on your specific history and factor XI level.

Treating Pregnancy With Factor XI Deficiency

The way we manage factor XI deficiency depends on each patient’s medical history as well as the severity of the condition. During pregnancy, we usually perform routine testing to check factor XI levels to have up-to-date information for your birth plan. We can treat factor XI deficiency with replacement therapy to help bolster your body’s natural production of the factor. For women with a severe deficiency, we sometimes administer replacement therapy with fresh frozen plasma prior to certain procedures, or shortly after labor begins and sometimes for up to two to four days after birth.  Whether someone does or does not need treatment, and for what procedures, is highly individualized based on your own history, factor XI level, and other pregnancy-related factors. So it is important to meet with one of us to make a plan prior to delivery to optimize your care and experience.

Genetic Screening at Carnegie Imaging for Women

Factor XI deficiency is just one of hundreds of genetic disorders we screen for in both the mother and baby during pregnancy. Not only does this provide parents with the information they need to make decisions about the future of their family but also about the health and safety of the act of childbirth. With state-of-the-art tools at our disposal, our genetic screening services help ensure you’re well cared-for every step of the way. Schedule your first appointment by calling our New York office or contacting us online today.

Carnegie Imaging for Women blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!

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