RCOG GTG 37a

VTE Prophylaxis (Pregnancy)

LMWH dosing by booking weight

Enoxaparin dose (prophylactic)

  • <50 kg: 20 mg SC OD
  • 50–90 kg: 40 mg SC OD
  • 91–130 kg: 60 mg SC OD
  • 131–170 kg: 80 mg SC OD
  • >170 kg: 0.6 mg/kg/day

Duration

  • Antenatal risk score ≥4: LMWH from booking until 6 wk postpartum.
  • Score = 3 antenatally: from 28/40 until 6 wk postpartum.
  • Any risk factor postnatal: at least 10 days.

Treatment dose (VTE)

  • Enoxaparin 1 mg/kg SC BD (booking weight).
  • Continue for remainder of pregnancy + ≥6 wk postpartum (min 3 months total).

Common mistakes

  • Stopping LMWH for elective CS <24 h before — needs 12–24 h break.
  • Warfarin in T1 → embryopathy (nasal hypoplasia, chondrodysplasia).
  • DOACs are contraindicated in pregnancy & breastfeeding.

For educational use only

Not medical advice. Verify dosing against the BNF and your local trust guidelines before prescribing.