How this calculator works
The October 2026 RCOG amendment changes several 2015 weights, including BMI at least 50 and transient surgical, infection and immobility risks. This page uses the amended points. Age above 35 scores one; BMI 30 to below 40 scores one, 40 to below 50 scores two, and at least 50 scores four. Medical comorbidity includes cancer, heart failure, active SLE, inflammatory polyarthropathy/IBD, nephrotic syndrome, type 1 diabetes with nephropathy, sickle cell disease or current IV drug use. Review the original definitions and specialist pathways. Admission, prior VTE, thrombophilia, persistent factors and bleeding risk may require action irrespective of the total. The result is an estimate for information only and is not medical advice.
Formula
Total = sum of applicable amended RCOG points. Prior VTE, thrombophilia and birth mode each use a single applicable category. ART contributes only antenatally. No anticoagulant dose is calculated.
Worked example
At age 36 and BMI 40 with no other factors, total is 1 + 2 = 3. BMI 50 alone gives four points under the October 2026 amendment.
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Frequently asked questions
Which guideline version is this?
The amended risk table in the RCOG October 2026 position statement, read with Green-top 37a, not the unamended 2015 table.
Does a low score mean no prophylaxis is needed?
No. Specialist and admission pathways, persistent risks and bleeding considerations cannot be reduced to this sum.
Can I use this to choose or dose an anticoagulant?
No. This is a scoring aid for clinical review. It supplies neither a drug choice nor a dose.