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Societal Recommendations

Timing of Neuraxial Anaesthesia with Commonly Used Anticoagulants

Thromboprophylactic Anticoagulation

Anticoagulant	ASRA	SOAP	ESAIC/ESRA	Association of Anaesthetists
Low-dose UFH (5000 U s.c. b.d. or t.d.s.)	Hold for 4–6 h OR assess coagulation status	Hold for 4–6 h OR assess coagulation status	Hold dose ≤200 IU kg⁻¹ day⁻¹ s.c. for 4 h	Hold for 4 h OR assess coagulation status
Low-dose LMWH (enoxaparin 40 mg s.c. daily, enoxaparin 30 mg s.c. b.d., dalteparin 5000 U s.c. daily)	Hold for 12 h	Hold for 12 h	Hold for 12 h	Hold for 12 h
Intermediate-dose UFH (7500 U s.c. b.d. or 10,000 U s.c. b.d.)	Hold for 12 h AND assess coagulation status	Hold for 12 h AND assess coagulation status (Insufficient data for a specific interval between 12 and 24 h)	No specific recommendation	No specific recommendation
Aspirin (any dose)	No limitations (Caution with other medications that might affect clotting)	No limitations (Caution with other medications that might affect clotting)	No limitations	No limitations

Therapeutic Anticoagulation

Anticoagulant	ASRA	SOAP	ESAIC/ESRA	Association of Anaesthetists
High-dose UFH (>10,000 U per dose or >20,000 U day⁻¹)	Hold for 24 h AND assess coagulation status	Hold for 24 h AND assess coagulation status	Wait until target laboratory values (aPTT, anti-Xa, ACT) are within normal range (-6 h if i.v. or 12 h if s.c.)	No specific recommendation
I.V. UFH infusion	Stop infusion for 4–6 h AND assess coagulation status	Stop infusion for 4–6 h AND assess coagulation status	Hold dose ≤100 IU kg⁻¹ day⁻¹ i.v. for 4 h	Stop infusion for 4 h OR assess coagulation status
High-dose LMWH (enoxaparin 1 mg kg⁻¹ s.c. b.d., enoxaparin 1.5 mg kg⁻¹ s.c. daily, dalteparin 120 U kg⁻¹ s.c. b.d., dalteparin 200 U kg⁻¹ s.c. daily)	Hold for 24 h	Hold for 24 h	Hold for 24 h	Hold for 24 h

Recommendations For Restarting Anticoagulation After Neuraxial Blockade and Epidural Catheter Removal

UFH (Unfractionated Heparin)

• Restarting s.c. or i.v. UFH after neuraxial placement or catheter removal: ASRA, SOAP, and the Association of Anaesthetists recommend a 1-hour interval. ESAIC/ESRA provides no specific recommendation.
• Restarting low-dose UFH thromboprophylaxis with an indwelling neuraxial catheter: ASRA and SOAP recommend waiting 4–6 hours or assessing coagulation status. ESAIC/ESRA advises holding doses ≤200 IU/kg/day s.c. for 4 hours. The Association of Anaesthetists suggests caution.
• In summary
  • Restating UFH after block/catheter removal: 1 hour
  • Restarting heparin with indwelling catheter: 4-6 hours or assessing coagulation status

LMWH (Low-Molecular-Weight Heparin)

• Restarting low-dose LMWH after neuraxial placement or catheter removal: ASRA advises 12 hours after placement and 4 hours after removal. SOAP has the same recommendation. The Association of Anaesthetists advises 4 hours and only one dose in the first 24 hours after neuraxial blockade. ESAIC/ESRA has no specific guidance.
• Restarting low-dose LMWH with an indwelling neuraxial catheter: ASRA, SOAP, and ESAIC/ESRA recommend 12 hours. The Association of Anaesthetists suggests caution.
• Restarting high-dose LMWH: ASRA and SOAP recommend 24 hours after neuraxial placement and 4 hours after catheter removal. The Association of Anaesthetists advises 4 hours, but 24 hours if the block was traumatic. ESAIC/ESRA provides no specific recommendation.
• In Summary
  • Prophylactic LMWH:
    • After block 12 hours ASA outlier at 4 hours with 1 dose in 24 hours
    • After catheter removal: 4 hours
    • Restarting: 12 hours
  • Therapeutic:
    • After block: 24 hours ASA outlier at 4hours, 24 hours if block was traumatic
    • After catheter removal: 4 hours
    • Restarting: 24 hours

Warfarin

• Peri-neuraxial recommendation (ASRA, ESAIC/ESRA):

  • Discontinue warfarin 5 days prior to neuraxial procedures.
  • Confirm INR is within normal range before proceeding.

• Pregnancy management:

  • In pregnant patients with mechanical heart valves, transition from warfarin to twice daily LMWH by:
    • 36 weeks’ gestation, or
    • 2 weeks prior to planned delivery (whichever is earlier).
  • Anti-Xa levels should be monitored while on LMWH.

• Breastfeeding:

  • Warfarin is considered safe in lactating patients.

• Epidural catheter management (ASRA):

  • Remove catheter when INR < 1.5.
  • Preferably remove within 12–24 hours of warfarin re-initiation.

Oral Direct Thrombin Inhibitors and Anti-Xa Inhibitors (DOACs)

• General considerations:
  • Rarely used during pregnancy.

Dabigatran (Direct Thrombin Inhibitor)

• Hold at least 72 hours before neuraxial block in patients with normal renal function (ASRA).
• After epidural catheter removal, allow ≥6 hours before restarting.

Rivaroxaban and Apixaban (Factor Xa Inhibitors)

• Hold at least 72 hours before neuraxial procedures.
• If <72 hours have elapsed, consider checking anti-Xa level before proceeding.
• After epidural catheter removal, allow ≥6 hours before restarting (ASRA).

Anticoagulation in Pregnancy

Elective Peripartum Management of Anticoagulation Therapy in Pregnant Women with Prosthetic Heart Valves

1. Stop warfarin at 36/40 weeks and switch to dose-adjusted SC-LMWH. If unavailable, use UFH infusion.
2. Last dose 24h before planned delivery at 38/40 weeks.
3. Bridge to dose-adjusted IV-UFH or intermittent LMWH (prophylactic dose) with various regimens.
4. Serial anti-Xa levels: 0.2 – 0.5 considered safe for vaginal or cesarean delivery.
5. Recommence IV-UFH or anti-Xa-guided SC-LMWH 6 hours after uncomplicated delivery.
6. Reintroduce warfarin on day 5 to 7 postpartum.

Therapeutically Anticoagulated Patient Who Requires Unscheduled Delivery

• Stop all anticoagulants immediately.

Management Based on Anticoagulant Type

1. Warfarin

   • Administer haemosolvex or FFP to target an INR of 2.0.
   • Small doses of Vitamin K orally or IV.

2. Therapeutic LMWH

   • Protamine reversal: 1 mg protamine per 1 mg Clexane given in the last 8 hours.

3. IV-UFH

   • Once stopped, coagulation should normalize within 1-2 hours.
   • Protamine if required (MOH risk): 1 mg per 100 units UFH given over the last 2-3 hours (max 50 mg).

SOAP Guidelines on the Peripartum Management of Women Receiving Thromboprophylaxis or Higher Dose Anticoagulants

Antepartum

1. Outpatient MDT consult at 36/40 weeks.
2. Thromboprophylactic regimens that facilitate neuraxial procedures e.g., converting LMWH to LD-UFH 5,000U SC BD.
3. If continuing LMWH, anticipate the need to withhold.
4. Flagging of such patients on admission.
5. Patients on UFH >4 days should have platelet counts checked before any neuraxial procedure to rule out HIT.

Intrapartum

• Admission for delivery should trigger an instruction to withhold anticoagulants and obtain obstetric advice for further management.

Postpartum

• Plan for resuming anticoagulation after delivery.

Postpartum Anticoagulant Recommencement and Neuraxial Catheter Removal

Subcutaneous UFH

• For SC UFH thromboprophylaxis:
  • Wait ≥1 hour after NB (no signs of PPH) and after CR before initiating or restarting UFH.
  • Indwelling catheters can be maintained with low dose UFH (5,000 U SC BD).
  • CR can occur 4-6 hours after a dose of UFH, with subsequent dosing ≥1 hour after CR.
  • Consider holding NSAIDs (excluding paracetamol).

Intravenous UFH

• Wait ≥1 hour after NB (if no signs of PPH) before initiating or restarting anticoagulation.

LMWH

• For low-dose LMWH thromboprophylaxis:
  • Wait ≥12 hours after NB and ≥4 hours after CR before initiating or restarting LMWH.
  • Indwelling catheters can be maintained with low-dose LMWH; CR ≥12 hours after LMWH, with subsequent dosing ≥24 hours after CR.
  • Consider holding NSAIDs.
• For higher dose LMWH:
  • Wait ≥24 hours after NB and ≥4 hours after CR before initiating or restarting LMWH.

NB = Neuraxial Block; CR = Catheter Removal

LMWH Dosing in Pregnancy (RCOG / CHEST 2022)

Booking weight	Prophylactic dose (enoxaparin)	Intermediate dose‡	Therapeutic dose
50–< 90 kg	40 mg SC OD	40 mg SC BD	1 mg kg⁻¹ SC BD
90–< 120 kg	40 mg SC BD	60 mg SC BD	1 mg kg⁻¹ SC BD
120–< 150 kg	60 mg SC BD	80 mg SC BD	1 mg kg⁻¹ SC BD
≥ 150 kg	80 mg SC BD (monitor anti-Xa 0.2–0.4 IU mL⁻¹)	100 mg SC BD	1 mg kg⁻¹ SC TDS ± monitoring

• ‡Used after caesarean in BMI ≥ 40 kg m⁻² or multiple major risk factors.
• Fondaparinux and DOACs are contra-indicated antenatally; warfarin is teratogenic (avoid weeks 6–12) but acceptable during breastfeeding.

Note: LMWH adjusted to a peak anti–factor Xa level of 0.5 to 1.0 U/mL (measured 3–4 hours after dose) or trough levels of 0.2 to 0.4 U/mL (measured 12 hours after dose). Anti–factor Xa assay must be calibrated to specific LMWH.

Links

• Clotting cascade
• Point of Care Coagulation testing
• Anticoagulation
• Anticoagulation and blocks
• Obstetric emergencies

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References:

1. Reale, S. C. and Farber, M. K. (2025). Peripartum management of the patient taking anticoagulant medications. BJA Education, 25(1), 20-28. https://doi.org/10.1016/j.bjae.2024.09.004
2. Recommendations for thromboprophylaxis in obstetrics and gynaecology E Schapkaitz. S Afr J Obstet Gynaecol 2018;24(1):xx-xx. DOI:10.7196/SAJOG.2018.v24i1.1312
3. Zaidi SRH, Jenkins SM. Anticoagulant Therapy In Pregnancy. [Updated 2024 Jan 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK606098/
4. Up-to-date. (n.d.). Use of anticoagulants during pregnancy and postpartum. Retrieved from https://www.uptodate.com/contents/use-of-anticoagulants-during-pregnancy-and-postpartum

Summaries:

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© 2025 Francois Uys. All Rights Reserved.

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