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PubMed This is a summary of 18 peer-reviewed journal articles Updated
Hematology

How Does Type O Blood Affect Von Willebrand Disease?

At a Glance

People with Type O blood naturally have up to 30% less Von Willebrand Factor (VWF) because their bodies clear the clotting protein faster. While this doesn't mean you have Von Willebrand Disease, it often causes borderline-low VWF levels and mild bleeding tendencies like heavy periods or nosebleeds.

In this answer

4 sections

01

Why Type O Blood Lowers Your VWF Levels

02

The “Type O Dilemma” and Modern Diagnosis

03

Does This Increase Your Bleeding Risk?

04

Navigating Procedures with Type O and Low VWF

Having Type O blood does not mean you automatically have Von Willebrand Disease (VWD). However, people with Type O blood naturally have about 25% to 30% less Von Willebrand Factor (VWF) in their bloodstream than people with other blood types [1]. Because of this natural physiological difference, having Type O blood frequently explains why someone has lower VWF levels and might experience mild bleeding tendencies [2].

Why Type O Blood Lowers Your VWF Levels

Von Willebrand Factor is a sticky protein that acts like glue to help your blood clot. The surface of the VWF protein is coated with complex sugars called glycans, which differ depending on your blood type [3]. If you have Type A, Type B, or Type AB blood, these specific sugars act as a protective shield, slowing down the natural breakdown of the VWF protein [4].

If you have Type O blood, your VWF proteins lack this protective shield. As a result, specific enzymes in your blood can break the protein down much more easily [5]. Your body then clears the VWF out of your bloodstream at a faster rate [6]. This rapid clearance is the primary biological reason why Type O individuals have lower overall levels of VWF [1].

The “Type O Dilemma” and Modern Diagnosis

Because individuals with Type O blood clear VWF faster, many naturally sit in the “borderline-low” lab range—which falls between 30 and 50 IU/dL [7][8]. This dynamic creates what doctors sometimes call the “Type O dilemma” [9].

In the past, doctors debated whether they should use different lab cutoffs based on a person’s blood type. However, modern clinical guidelines recognize that the absolute amount of VWF in your blood is what determines your true bleeding risk, regardless of your blood type [10]. Therefore, the diagnostic cutoffs are applied universally:

  • True Type 1 VWD: VWF levels fall below 30 IU/dL [11].
  • Low VWF: VWF levels are between 30 and 50 IU/dL [8].

To ensure an accurate diagnosis and prevent mistakenly labeling a healthy Type O person with a disease, hematologists do not adjust the lab reference ranges. Instead, they pair your blood tests with a Bleeding Assessment Tool (BAT) [12]. A BAT is a standardized questionnaire used to carefully measure and score your actual real-world history of bleeding symptoms [11].

Does This Increase Your Bleeding Risk?

Having borderline-low VWF levels (30-50 IU/dL) due to Type O blood does not mean you have a classic disease, but it can mean you are slightly more prone to mild bleeding [13][14]. People categorized as having “Low VWF” might experience:

  • Slightly heavier menstrual periods
  • More frequent or prolonged nosebleeds
  • Minor oozing or extended bleeding after dental work or minor cuts [8]

If you actually meet the formal diagnostic criteria for VWD (levels below 30 IU/dL), your bleeding symptoms are generally more pronounced and require active, ongoing medical management, regardless of whether you have Type O blood [15].

Even if you are diagnosed with “Low VWF” rather than true VWD, your bleeding risk remains an important factor for medical planning. When it comes to surgeries, childbirth, or major dental work, your body may need extra help forming strong clots [16].

You should proactively inform your surgeons and dentists about your low VWF levels. Depending on your history, your care team might recommend simple pre-procedure plans. This could include avoiding blood-thinning medications like NSAIDs (such as ibuprofen) or using specific medications like tranexamic acid (TXA) or desmopressin (DDAVP) to temporarily boost your body’s clotting ability during and after the procedure [17][18].

Common questions in this guide

Can You Develop Von Willebrand Disease Later in Life?Can You Get an Epidural with Von Willebrand Disease?Can You Have Iron Deficiency Without Anemia in VWD?Can You Play Sports with Von Willebrand Disease?Does Stress Affect Von Willebrand Disease Test Results?How Do Antifibrinolytics Work for VWD Bleeding?How Is Von Willebrand Disease Inherited?Dental Work with Von Willebrand Disease: How to PrepareIs an IUD Safe for Women with Von Willebrand Disease?What Causes Delayed Postpartum Hemorrhage in VWD?What is a DDAVP Challenge Test for Von Willebrand Disease?What Is a Heavy Period with Von Willebrand Disease?Low VWF vs. Type 1 VWD: What is the Difference?Type 2N VWD vs. Hemophilia A: What's the Difference?Does Von Willebrand Disease Affect Life Expectancy?What Pain Meds Are Safe for Von Willebrand Disease?What's in a VWD Emergency Travel Letter?When Are Nosebleeds a Sign of Von Willebrand Disease?Why Must I Restrict Fluids After DDAVP?
Does having Type O blood mean I have Von Willebrand Disease?
No, having Type O blood does not automatically mean you have Von Willebrand Disease. However, people with Type O blood naturally have about 25% to 30% less Von Willebrand Factor, which can sometimes result in mild bleeding tendencies or a 'Low VWF' classification.
Why do people with Type O blood have lower Von Willebrand Factor levels?
In people with Type O blood, the Von Willebrand Factor protein lacks a protective sugar shield found in other blood types. Without this shield, enzymes can break the protein down more easily, causing the body to clear it from the bloodstream at a much faster rate.
What is the difference between 'Low VWF' and true Type 1 Von Willebrand Disease?
True Type 1 Von Willebrand Disease is diagnosed when your VWF levels fall below 30 IU/dL and usually involves more pronounced bleeding. 'Low VWF' is a borderline range between 30 and 50 IU/dL, which is very common in people with Type O blood and generally causes milder symptoms.
What precautions should I take for surgery if I have Low VWF from Type O blood?
You should proactively inform your surgeon and dentist about your lower clotting levels. Your care team may recommend avoiding blood-thinning medications like ibuprofen or prescribe specific medications like tranexamic acid (TXA) to help your blood clot properly during the procedure.

Questions for Your Doctor

4 questions

  • •Since I have Type O blood, do my VWF levels reflect a natural baseline, or do they fall low enough to indicate true Type 1 Von Willebrand Disease?
  • •Should we complete a formal Bleeding Assessment Tool (BAT) questionnaire to get a clearer, more objective picture of my bleeding history?
  • •How does my 'Low VWF' status change how we should plan for any upcoming surgeries, childbirth, or major dental work?
  • •Are there specific over-the-counter medications, like ibuprofen or other NSAIDs, that I should strictly avoid given my blood type and clotting levels?

Questions for You

3 questions

  • •Have I actually experienced noticeable bleeding symptoms over my lifetime—such as frequent nosebleeds, unusually heavy periods, or prolonged bleeding from minor cuts—or am I primarily concerned because of an unexpected lab result?
  • •Have any of my blood relatives (especially those with Type O blood) been diagnosed with a bleeding disorder or experienced severe bleeding after surgeries?
  • •What procedures or dental work do I have coming up where I need to proactively inform the provider about my lower Von Willebrand Factor levels?

References

References (18)
  1. 1

    Unraveling the Influence of Common von Willebrand factor variants on von Willebrand Disease Phenotype: An Exploratory Study on the Molecular and Clinical Profile of von Willebrand Disease in Spain Cohort.

    Borràs N, Garcia-Martínez I, Batlle J, et al.

    Thrombosis and haemostasis 2020; (120(3)):437-448 doi:10.1055/s-0040-1702227.

    PMID: 32135566
  2. 2

    Clinical and laboratory presentation of von Willebrand disease: Experience from a single center in Saudi Arabia.

    Owaidah T, Alharbi M, Mandourah M, et al.

    Journal of Taibah University Medical Sciences 2023; (18(2)):413-419 doi:10.1016/j.jtumed.2022.10.019.

    PMID: 37102076
  3. 3

    ABO blood group is related to bleeding in cardiac surgery.

    Hansen SM, Sprogøe U, Möller S, Andersen C

    Acta anaesthesiologica Scandinavica 2021; (65(4)):466-472 doi:10.1111/aas.13749.

    PMID: 33215688
  4. 4

    ABO blood group is a determinant of von Willebrand factor protein levels in human pulmonary endothelial cells.

    Murray GP, Post SR, Post GR

    Journal of clinical pathology 2020; (73(6)):347-349 doi:10.1136/jclinpath-2019-206182.

    PMID: 31662441
  5. 5

    ABO-dependent manner modulates hemostasis in neonatal thrombocytopenia via ADAMTS13-mediated VWF cleavage.

    Liang C, Chen X, Huang Y, Wei X

    Pediatrics and neonatology 2025; doi:10.1016/j.pedneo.2025.05.011.

    PMID: 41193285
  6. 6

    Aging and ABO blood type influence von Willebrand factor and factor VIII levels through interrelated mechanisms.

    Albánez S, Ogiwara K, Michels A, et al.

    Journal of thrombosis and haemostasis : JTH 2016; (14(5)):953-63 doi:10.1111/jth.13294.

    PMID: 26875505
  7. 7

    Unravelling the spectrum of von Willebrand factor variants in quantitative von Willebrand disease: results from a German cohort study.

    Krahforst A, Yadegari H, Pavlova A, et al.

    Journal of thrombosis and haemostasis : JTH 2024; (22(11)):3010-3034 doi:10.1016/j.jtha.2024.06.026.

    PMID: 39002731
  8. 8

    Management of elective procedures in low von Willebrand factor patients in the LoVIC study.

    Doherty D, Lavin M, O'Sullivan JM, et al.

    Journal of thrombosis and haemostasis : JTH 2021; (19(3)):701-710 doi:10.1111/jth.15220.

    PMID: 33346399
  9. 9

    Low von Willebrand factor-unraveling an enigma wrapped in a conundrum.

    O'Donnell JS, Baker RI, Atiq F

    Journal of thrombosis and haemostasis : JTH 2024; (22(12)):3383-3388 doi:10.1016/j.jtha.2024.08.015.

    PMID: 39265913
  10. 10

    Diagnosis of von Willebrand disease.

    Bowman M, James P

    Blood advances 2025; (9(22)):5870-5879 doi:10.1182/bloodadvances.2025016485.

    PMID: 40845253
  11. 11

    Longitudinal bleeding assessment in von Willebrand disease utilizing an interim bleeding score.

    Lavin M, Christopherson P, Grabell J, et al.

    Journal of thrombosis and haemostasis : JTH 2022; (20(10)):2246-2254 doi:10.1111/jth.15807.

    PMID: 35780487
  12. 12

    How I treat von Willebrand disorders in older adults.

    Poston JN, Kruse-Jarres R

    Blood 2024; (143(3)):197-204 doi:10.1182/blood.2022018534.

    PMID: 37672774
  13. 13

    Investigating patients for bleeding disorders when most of the "usual" ones have been ruled out.

    Mehic D, Pabinger I, Gebhart J

    Research and practice in thrombosis and haemostasis 2023; (7(8)):102242 doi:10.1016/j.rpth.2023.102242.

    PMID: 38193045
  14. 14

    Blood group O: A novel risk factor for increased postpartum blood loss?

    Kahr MK, Franke D, Brun R, et al.

    Haemophilia : the official journal of the World Federation of Hemophilia 2018; (24(4)):e207-e212 doi:10.1111/hae.13537.

    PMID: 29877601
  15. 15

    Knowledge of Blood Group Decreases von Willebrand Factor Panel Testing in Children.

    Archer NM, Forbes PW, Brugnara C

    HemaSphere 2017; (1(1)):e3 doi:10.1097/HS9.0000000000000003.

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  16. 16

    Analysis of current perioperative management with Haemate® P/Humate P® in von Willebrand disease: Identifying the need for personalized treatment.

    Hazendonk HCAM, Heijdra JM, de Jager NCB, et al.

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    PMID: 29573506
  17. 17

    Low von Willebrand Disease: A Bleeding Disorder of Unknown Cause?

    O'Donnell JS, Baker RI

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  18. 18

    Perioperative management of von Willebrand patients at the time of implant placement: Case report.

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    PMID: 34484779

This page explains how blood type affects Von Willebrand Factor levels for educational purposes only. Always consult a hematologist or your healthcare provider for an accurate evaluation of your bleeding risks and laboratory results.

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