Enter age, height and weight or BMI, select pregnancy or postpartum, and add optional risk factors. The calculator totals VTE (venous thromboembolism) risk points and shows a simple risk band. Use with a clinician.
What this tool calculates
- A point based pregnancy and postpartum venous thromboembolism (VTE) risk score styled on RCOG 37a risk assessment.
- A simple banded interpretation: 0 to 1 low, 2 to 3 moderate, 4 or more higher.
Inputs and point scheme
- Age 35 or older: 1 point.
- Body mass index: 1 point if BMI 30 or more, 2 points if BMI 40 or more.
- Pre existing factors: previous VTE, thrombophilia, selected medical comorbidities, family history, parity 3 or more, smoking, gross varicose veins. Points match the values shown in the calculator.
- Obstetric factors: pre eclampsia, assisted reproduction, multiple pregnancy, mode of birth, prolonged labour, postpartum haemorrhage, preterm birth, stillbirth. Points match the values shown in the calculator.
- Transient factors: surgery in pregnancy or puerperium, hyperemesis, ovarian hyperstimulation syndrome, systemic infection, immobility or dehydration. Points match the values shown in the calculator.
Computation
- Total score equals the sum of selected item points.
- Bands provide a plain language summary to support counselling. Decisions follow local protocol.
BMI handling
- If height and weight are entered, BMI is calculated from the chosen units.
- If left blank, BMI defaults to 26 so obesity points are not applied.
Scope and limits
- Use in pregnancy and up to 6 weeks postpartum for singleton pregnancies.
- Risk assessment should be repeated with changes in status, admission, or at birth, in line with guideline practice.
- This tool does not initiate, adjust, or withhold treatment. Use shared decision making and local pathways.
Sources
- RCOG Green top Guideline 37a, Reducing the risk of thrombosis and embolism during pregnancy and the puerperium. Guideline page and PDF: rcog.org.uk guideline page, rcog.org.uk PDF.
- NICE resource, RCOG obstetric thromboprophylaxis risk assessment tool (score sheet). nice.org.uk risk tool PDF.
- ACOG Practice Bulletin, Thromboembolism in Pregnancy, overview page. acog.org practice bulletin.
- Queensland Health Clinical Guideline, VTE prophylaxis in pregnancy and the puerperium. health.qld.gov.au PDF.
Last updated: 26 Sep 2025
How to use this calculator
- Select units, then enter height and weight, or leave blank to use a typical BMI of 26.
- Enter age, or tick 35 or older to apply that item.
- Select pregnancy or postpartum.
- Open Advanced to add optional risk factors. Each item shows its points.
- Press Calculate. The output shows the total score, the BMI used, and a simple risk band.
For counselling only. Use with clinical judgement and local guidance.
Last updated: September 2025
Frequently asked questions
What does this VTE score show?
A point total that reflects venous thromboembolism risk in pregnancy or postpartum. It groups results into low, moderate, or higher risk bands.
Which items add points?
Age 35 or older, higher BMI, selected pre-existing, obstetric, and transient factors. Each item lists its points in the Advanced section.
Can I leave height and weight blank?
Yes. The tool will use a typical pre-pregnancy BMI of 26 if no height and weight are entered.
Is this a diagnosis?
No. It supports counselling. A clinician should interpret the score with your history and local protocols.
What symptoms need urgent care?
Sudden shortness of breath, chest pain, coughing blood, a swollen or painful leg, or fainting need urgent assessment.