π€° Pregnancy VTE Risk Checker
Which clot risk factors apply to you?
Risk factor count
For informational purposes only, not medical advice.
Pregnancy raises clot risk about fivefold through Virchow's triad: hypercoagulability, venous stasis, and vessel injury. RCOG guidance lists the risk factors that stack on top: prior VTE or thrombophilia dominates, while age over 35, obesity, smoking, high parity, immobility, and pre-eclampsia each add weight. Three minor factors, say age 35+, BMI 30+, and smoking, screen as Intermediate: discuss prophylaxis in this educational checklist.
Thromboembolism remains a leading cause of maternal mortality in developed countries, which is why every pregnancy deserves a formal VTE risk assessment. The assessment is quick; missing it is costly.
How to Use This Checker
Answer the eight questions about history and this pregnancy. The tool flags the risk band and reminds you what needs a provider conversation.
Answer the major factors: any prior VTE and any known thrombophilia. Either one alone puts you in the high band.
Answer the additional factors: age, BMI, parity, smoking, immobility, and pre-eclampsia.
Read the band. Intermediate or high means asking your provider specifically about thromboprophylaxis, not waiting to be offered it.
Why Pregnancy Clots
The hypercoagulability is evolutionary: it protects against hemorrhage at delivery, but it overshoots in susceptible women. Risk peaks postpartum, especially after cesarean, which is why assessments repeat after birth. Dehydration, long travel, and ovarian hyperstimulation add further, situational risk.
Prophylaxis, usually weight-based low-molecular-weight heparin, is remarkably effective, which makes risk assessment one of the highest-value checklists in obstetrics. The tragedy cases are almost always unassessed, not untreatable.
Worked Example
A 36-year-old smoker with BMI 32 and no prior clots: yes to age, BMI, and smoking, three minor factors, screening as Intermediate: discuss prophylaxis. Her provider would weigh antenatal prophylaxis, and certainly reassess postpartum, when the same factors plus delivery itself push risk higher.
Contrast a 28-year-old non-smoker, BMI 24, first pregnancy: no factors, low band, routine care with reassessment if circumstances change, for example prolonged bed rest or a cesarean. The checklist sorts the two in under a minute.
Reading Your Result
| Band | Meaning |
|---|---|
| Low | Routine care, early mobilization, hydration, reassess if things change. |
| Intermediate | Discuss prophylaxis with your provider; often recommended around delivery and postpartum. |
| High | Antenatal prophylaxis commonly recommended; needs specialist planning. |
My take: ask the explicit question at your booking visit: what is my VTE risk score and do I need prophylaxis? It takes thirty seconds, it is guideline-recommended, and it occasionally gets skipped in busy clinics. The checklist in your hand makes the question easy.
Limits
This is a simplified educational checklist, not the full RCOG scoring system, which weighs factors differently and includes items like gross varicose veins, family history, and assisted reproduction. It cannot see your full history, and prophylaxis decisions involve bleeding risk trade-offs only your provider can weigh. Use it to start the conversation, not to conclude it.
Related Tools
Track the pregnancy with the pregnancy due date calculator and monitor pressure, a pre-eclampsia factor, with the blood pressure checker.
For informational purposes only, not medical advice. Consult a healthcare professional.
Frequently Asked Questions
Why does pregnancy increase blood clot risk?
Pregnancy creates Virchow's triad: clotting factors rise, venous flow slows (especially with the uterus compressing pelvic veins), and vessel injury occurs at delivery. Risk rises about fivefold antenatally and higher postpartum.
What are the main VTE risk factors in pregnancy?
Prior VTE and thrombophilia dominate. Additional factors include age 35+, obesity, smoking, parity of 3+, immobility, pre-eclampsia, gross varicose veins, multiple pregnancy, and cesarean delivery.
When is blood clot risk highest in pregnancy?
Postpartum, particularly the first weeks after delivery, and higher after cesarean than vaginal birth. Antenatal risk is elevated throughout but peaks near term.
What is thromboprophylaxis in pregnancy?
Preventive blood thinners, usually weight-based low-molecular-weight heparin injections, given to at-risk women during pregnancy and postpartum. It is highly effective and the standard recommendation for high-risk bands.
What are signs of DVT or PE in pregnancy?
Leg swelling or pain (especially one-sided), chest pain, sudden breathlessness, rapid heartbeat, or coughing blood. These need emergency evaluation; pregnancy symptoms can mask them, so err toward checking.
Can you fly while pregnant with clot risk?
Long flights add stasis risk. Guidance includes hydration, movement, compression stockings, and for high-risk women, discussing prophylaxis before travel. Discuss long-haul plans with your provider.
Does family history of clots matter?
Yes, it raises suspicion for inherited thrombophilia and counts in formal risk assessment. Tell your provider about first-degree relatives with VTE, especially at young ages.
Is heparin safe in pregnancy?
Low-molecular-weight heparin does not cross the placenta and is the standard anticoagulant in pregnancy. Warfarin is avoided (teratogenic). Dosing and duration are set by your specialist.
Should every pregnant woman be risk-assessed?
Yes. RCOG and other guidelines recommend VTE risk assessment at booking, during pregnancy if circumstances change, and postpartum. Ask for it explicitly if it is not mentioned.
Does this checker replace the RCOG score?
No. It is a simplified educational checklist of the major factors. The full RCOG assessment weighs more factors and sets prophylaxis; your provider performs the official version.