Review Note

• Previous DVT/PE with conditions like:
  • Factor V Leiden
  • Protein C/S deficiency
  • Antiphospholipid syndrome
  • G20210T mutation
• Valvular heart disease or prosthetic heart valves
• Significant pulmonary hypertension (although pregnancy is usually not recommended in such cases)
• Cerebral venous sinus thrombosis
• Atrial fibrillation

• Warfarin is contraindicated in pregnancy due to teratogenic risks. (increased risk 1st trimester)
• NOACs (Non-Vitamin K Oral Anticoagulants) are generally avoided during pregnancy due to limited experience and insufficient evidence regarding their safety for both mother and fetus.
• Heparins (Low Molecular Weight Heparin [LMWH] and Unfractionated Heparin [UFH]) are preferred as they do not cross the placenta and are more readily reversible with protamine.

• Enoxaparin: 1 mg/kg twice daily.
• Dalteparin: 100 units/kg twice daily.
• Once-daily dosing is avoided to prevent high peak and low trough anti-Xa activity, which may lead to ineffective anticoagulation.

• LMWH at therapeutic doses is contraindicated for neuraxial anaesthesia.
• Switch to UFH prior to delivery is recommended for more flexibility in anaesthesia management.
  • Spinal blocks: Should be performed at least 6 hours after UFH or 12 hours after LMWH.
  • Epidural catheters: Should be removed before the next dose of LMWH is given, with a 2-hour delay before administering the next dose.

• Pregnant women on anticoagulants should be counselled about the increased risk of epidural haematoma, particularly in procoagulant states, which are already heightened during pregnancy. This risk is further exacerbated by anticoagulation therapy, especially when there is insufficient time between anticoagulant doses and neuraxial procedures.

Key Points:

• Therapeutic doses of LMWH are contraindicated for neuraxial anaesthesia.
• A switch to UFH before delivery offers flexibility in managing neuraxial anaesthesia.
• Timing of spinal and epidural procedures is crucial (6 hrs post-UFH, 12 hrs post-LMWH).
• Counseling on the risk of haematoma is important for patients on anticoagulants, especially during the peripartum period.