AKT · Obstetrics & gynaecology/Antenatal & medical

VTE in pregnancy and the puerperium

Pregnancy hypercoagulability

Overview

Pregnancy and the puerperium are prothrombotic (Virchow’s triad) — VTE is a leading direct cause of maternal death. Risk is highest postpartum. Assessed with a risk score; treated and prevented with LMWH (NOT warfarin/DOACs).

Recognise

DVT: unilateral (usually LEFT) leg swelling/pain
PE: breathlessness, pleuritic chest pain, tachycardia, hypoxia
Risk highest in the postnatal period

Red flags

Suspected PE with instability → emergency; massive PE

Differentials & how to tell them apart

Physiological leg swellingbilateral, no pain/erythema

Cellulitiserythema, warmth, fever

Musculoskeletal/respiratory causesimaging

Investigations

Do not withhold treatment while investigating. DVT: compression duplex USS. PE: CXR then V/Q or CTPA. D-dimer is unhelpful in pregnancy (physiologically raised).

Management

Low-molecular-weight heparin (treatment-dose)

1Risk-assess every woman (booking, antenatal admissions, postnatally). Prophylactic LMWH for those above the risk threshold.Gate: Use LMWH, NOT warfarin or DOACs — warfarin is teratogenic; DOACs are not recommended in pregnancy/breastfeeding
2Confirmed/strongly suspected VTE: treatment-dose LMWH; continue for the pregnancy and ≥6 weeks postpartum (and ≥3 months total).

Low-molecular-weight heparin (LMWH) — treatment AND prophylaxis — does not cross placenta

AVOID warfarin (teratogen) and DOACs — in pregnancy/breastfeeding

Key points

D-dimer is not useful (raised in normal pregnancy). LMWH is the anticoagulant throughout. Risk is greatest postpartum — assess and prophylax after delivery.

Monitor & prognosis

Symptoms, anti-Xa in selected cases; bleeding; convert to warfarin/DOAC only postnatally if needed.

Good with prompt anticoagulation.

Source: RCOG Green-top 37a/b