Obstetrics & Gynaecology Haematology Strong — RCOG Green-top GTG37a

VTE Risk in Pregnancy (RCOG)

RCOG Green-top Guideline 37a antenatal VTE risk score (Appendix III), at booking and on any admission. Reassess at delivery with the postnatal factors (caesarean, PPH, prolonged labour, preterm birth, stillbirth).

Previous VTE*

Known thrombophilia*

Medical comorbidity: cancer, heart failure, active SLE, inflammatory polyarthropathy or IBD, nephrotic syndrome, type 1 diabetes with nephropathy, sickle cell disease, or current IV drug use*

Family history of unprovoked or oestrogen-related VTE in a first-degree relative*

Age > 35 years*

BMI at booking*

Parity ≥ 3*

Smoker*

Gross varicose veins (symptomatic, above the knee, or with phlebitis, oedema or skin changes)*

Pre-eclampsia in the current pregnancy*

ART / IVF pregnancy*

Multiple pregnancy*

Any surgical procedure in pregnancy (e.g. appendicectomy)*

Hyperemesis*

Ovarian hyperstimulation syndrome (first trimester only)*

Current systemic infection*

Immobility or dehydration*

Score interpretation

Lower Risk Antenatally (Score 0–2) 0–2

Antenatal score below the RCOG threshold for antenatal LMWH.

→ Mobilisation and avoidance of dehydration. If admitted to hospital, consider LMWH. Reassess at delivery: a postnatal score ≥ 2 → consider LMWH for at least 10 days.

Score 3 — Consider LMWH From 28 Weeks 3

Three current risk points (RCOG GTG 37a).

→ Consider prophylactic LMWH from 28 weeks; usually 6 weeks postnatally after a postnatal reassessment. Consider LMWH on any admission.

Score ≥ 4 — Consider LMWH From the First Trimester 4–32

Four or more current risk points (RCOG GTG 37a).

→ Consider prophylactic LMWH throughout the antenatal period; usually 6 weeks postnatally after a postnatal reassessment. Any previous VTE (other than a single surgery-related event) is high risk: antenatal LMWH and referral to the trust's thrombosis-in-pregnancy expert or team.

Interpretation bands for the VTE Pregnancy. Apply clinical judgement and local guidance.

References

RCOG Green-top Guideline No. 37a. Reducing the Risk of Venous Thromboembolism during Pregnancy and the Puerperium. 2015 (Appendix I and III).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Padua Prediction Score (VTE Risk) · VTE Prevention

Drugs

Pathways

Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.

Score interpretation

References

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