Clinical Resources for Clinicians · For clinicians
Heavy Menstrual Bleeding: Bleeding Disorder Workup and VWD Screening
Every patient with heavy menstrual bleeding should get a structured bleeding history. Those who screen positive need a CBC, PT/aPTT and specific von Willebrand testing: VWF antigen, VWF activity and factor VIII. Under the 2021 ASH ISTH NHF WFH guideline, VWF below 0.30 IU/mL is diagnostic of type 1 VWD, and below 0.50 IU/mL is diagnostic in a patient with abnormal bleeding. Estrogen, pregnancy and inflammation all raise VWF, so interpret in context and repeat when suspicion is high.
In practice, the miss usually isn't that nobody thought of VWD. It's that a PT and aPTT came back normal, or VWF was drawn while the patient was on a combined pill, and the chart says "coag workup negative" for the next ten years.
Why it matters in gynecology
Von Willebrand disease is the most common inherited bleeding disorder, and HMB is often its first and main symptom in women. ACOG Committee Opinion 785 notes that bleeding disorders turn up in a substantial minority of adolescents evaluated for HMB, around one in five in referral cohorts, second only to anovulation in that age group. The yield is lower in adults but still clinically meaningful.
The cost of missing it: years of iron deficiency, procedures that didn't need to happen, "unexplained" postpartum hemorrhage, and surgical bleeding that a hemostatic plan would have prevented.
Step 1: Take a structured bleeding history
ACOG screening criteria
ACOG Committee Opinion 557 includes a screening history for an underlying bleeding disorder. A positive screen is any of:
- HMB since menarche
- One of: postpartum hemorrhage, surgery-related bleeding, or bleeding with dental work
- Two or more of: bruising one to two times a month, epistaxis one to two times a month, frequent gum bleeding, or a family history of bleeding symptoms
A positive screen warrants laboratory testing and, typically, hematology involvement.
ISTH-BAT
The ISTH Bleeding Assessment Tool gives a standardized, scored history. Commonly cited abnormal cutoffs: 6 or more in adult women, 4 or more in adult men, 3 or more in children. ASH 2021 suggests a validated BAT as an initial screen when probability of VWD is low, such as in primary care. It doesn't suggest using a BAT to decide who gets blood tests when probability is intermediate or high; those patients go straight to labs.
The menstrual history questions that earn their time
Patients who've always bled heavily often don't know it's abnormal. Ask concretely:
- Flooding, or changing pads or tampons every 1–2 hours
- Clots larger than about an inch
- Periods lasting more than 7 days
- Changing overnight, or doubling up protection
- Iron deficiency or a prior transfusion
- HMB from the very first period
"Have you ever bled through onto a chair or your sheets?" tends to get a more accurate answer than "Are your periods heavy?"
Step 2: Order the right first-line labs
| Test | Purpose | Interpretation caveats |
|---|---|---|
| CBC with platelets | Anemia, thrombocytopenia | Platelet count is normal in most VWD; low in type 2B |
| Ferritin | Iron deficiency | Treat iron deficiency regardless of the VWD result |
| PT / aPTT | Factor deficiencies | aPTT is often normal in type 1 VWD; don't use it to exclude VWD |
| Fibrinogen (optional) | Hypo/dysfibrinogenemia | Consider with abnormal screening tests |
| VWF antigen (VWF:Ag) | Quantity of VWF | Raised by estrogen, pregnancy, inflammation, stress |
| VWF activity (GPIbM, GPIbR or VWF:RCo) | Platelet-binding function | ASH suggests newer GPIb-binding assays over VWF:RCo |
| Factor VIII activity | Carried by VWF; low in some VWD and in hemophilia A carriers | Hemophilia A or B carriers may also have HMB |
The PFA-100 isn't a reliable screen for mild VWD and doesn't substitute for specific VWF assays.
Step 3: Interpret against ASH 2021
| Result | Interpretation |
|---|---|
| VWF (antigen or activity) < 0.30 IU/mL | Type 1 VWD, regardless of bleeding history |
| VWF 0.30–0.50 IU/mL with abnormal bleeding | Type 1 VWD |
| VWF 0.30–0.50 IU/mL without abnormal bleeding | Often labeled "low VWF"; individualize with hematology input |
| VWF activity/antigen ratio < 0.7 | Suggests a type 2 variant; needs specialized testing |
| Normal VWF with high suspicion | Repeat testing; consider platelet function disorders and factor deficiencies |
Pre-analytic pitfalls
VWF is an acute-phase reactant. Things that push it up:
- Estrogen-containing contraception and pregnancy, which can normalize levels in mild VWD
- Acute illness, inflammation, surgery or recent bleeding
- Stress, exercise or a difficult draw, classically a distressed adolescent after three needle attempts
- Sample handling: processing delays or improper cold storage can falsely lower results. Use a lab experienced with VWF testing. If your practice sends out through a courier, ask the lab how samples should be handled.
Blood group O is associated with lower VWF levels. Some group O patients with borderline levels still have a clinically significant bleeding phenotype, which is why ASH pairs levels with bleeding history.
Practical tip: if the first set is normal but your suspicion is high, repeat it, ideally when the patient is well and, where feasible, off estrogen. Some clinicians time the draw to early in the cycle, when VWF tends to be lowest. Don't pull effective hormonal therapy from someone who's bleeding heavily just to get a cleaner test; work out timing with hematology.
Step 4: Look beyond VWD
If VWF studies are normal but the phenotype is convincing, consider:
- Platelet function disorders. These need aggregation studies at a specialized lab, with NSAIDs, aspirin and SSRIs held first.
- Factor deficiencies, for example factor XI deficiency, which can present with a normal or mildly prolonged aPTT and is more common in Ashkenazi Jewish populations. In Brooklyn, Rockland and parts of Long Island, that's not an academic point.
- Hemophilia carriers, whose factor VIII or IX levels can be low.
- Rare fibrinogen disorders.
These evaluations belong with hematology.
Management while the workup proceeds
- Treat iron deficiency with oral or IV iron, whatever the final diagnosis.
- Hormonal options (combined hormonal contraception, LNG-IUD, progestins) work for HMB in patients with VWD. ASH 2021 suggests hormonal therapy or tranexamic acid for HMB in women with VWD who don't want to become pregnant.
- Tranexamic acid during menses is an effective nonhormonal option. Review thrombosis risk and concurrent estrogen use.
- Desmopressin is used in responsive type 1 VWD after a hematology-supervised trial, with fluid restriction and sodium monitoring.
- Surgery and procedures: ablation and hysterectomy need a hemostatic plan if VWD is suspected. Don't proceed to elective surgery with an unexplained bleeding history.
One sequencing note: starting a combined hormonal method before the VWF draw is common and understandable, but document it on the lab requisition so whoever interprets the result knows.
Planning for pregnancy
VWF rises in pregnancy and falls quickly after delivery, so patients with VWD face a particular risk of delayed postpartum hemorrhage. Share a known or suspected diagnosis with the obstetric and anesthesia teams early. See VWD in pregnancy and delivery planning.
Make the diagnosis travel with the patient
Once a bleeding disorder is confirmed, or remains strongly suspected:
- Add it to the problem list with the type and baseline levels.
- Give the patient a written summary or bleeding-disorder card for emergency visits.
- Flag the chart for surgical and procedural planning.
Patients in New York often get care across multiple health systems whose records don't talk to each other. The card in her wallet is sometimes the only thing the ED at another hospital sees.
Common pitfalls
- Ordering only a PT and aPTT and calling the workup negative
- Testing VWF on estrogen and never repeating it
- Not treating iron deficiency while the diagnosis is pending
- Skipping the history in adults because "bleeding disorders are a pediatric thing"
For the adolescent-specific angle, see iron deficiency without anemia in adolescents with HMB.
Referral partnership in New York
A positive bleeding screen, a borderline VWF result, or unexplained iron deficiency in a patient with HMB is a natural point for shared care. Premier Hematology & Oncology, which sponsors our professional resources, offers referral pathways for bleeding-disorder evaluation, fast-track IV iron scheduling and co-management across New York. See our hematology partners page.
Frequently asked questions
Who should be screened for a bleeding disorder with heavy menstrual bleeding?
ACOG recommends a structured bleeding history for all patients with heavy menstrual bleeding, with laboratory testing when the history is positive: HMB since menarche, a history of postpartum, surgical or dental bleeding, or two or more minor bleeding symptoms or a family history.
What labs screen for von Willebrand disease?
Initial testing typically includes a CBC with platelets, PT and aPTT, and specific VWF testing: VWF antigen, a VWF platelet-binding activity assay, and factor VIII activity. A normal aPTT does not exclude VWD.
What VWF level is diagnostic of VWD?
Under the 2021 ASH ISTH NHF WFH guideline, a VWF level below 0.30 IU/mL confirms type 1 VWD regardless of bleeding, and a level below 0.50 IU/mL confirms it in a patient with abnormal bleeding.
Do oral contraceptives affect VWF testing?
Yes. Estrogen raises VWF and can mask mild VWD. Pregnancy, inflammation, stress and exercise do the same, so a single normal result in these settings doesn't rule out VWD.
Sources
- ACOG — Management of Acute Abnormal Uterine Bleeding in Nonpregnant Reproductive-Aged Women (Committee Opinion No. 557)
- ACOG — Screening and Management of Bleeding Disorders in Adolescents With Heavy Menstrual Bleeding (Committee Opinion No. 785)
- ASH ISTH NHF WFH — 2021 guidelines on the diagnosis of von Willebrand disease
- ASH ISTH NHF WFH — 2021 guidelines on the management of von Willebrand disease
- ISTH — Bleeding Assessment Tool (ISTH-BAT)
This article is for general education and is not medical advice. It does not replace an evaluation by a licensed clinician who knows your history. If you think you have a medical emergency, call 911.