When are pregnant patients with thrombocytopenia (low platelet count) started on anticoagulants?

Anticoagulation in Pregnant Patients with Thrombophilia

Pregnant patients with thrombophilia should receive anticoagulation based on their specific risk factors, with low molecular weight heparin (LMWH) being the preferred agent for those requiring treatment. The decision to initiate anticoagulation depends on the type of thrombophilia, history of venous thromboembolism (VTE), and family history.

Risk Stratification for Anticoagulation in Pregnancy

High Risk - Require Antepartum Prophylaxis

• Pregnant women with prior history of VTE should receive postpartum prophylaxis for 6 weeks with prophylactic or intermediate-dose LMWH or vitamin K antagonists (INR 2.0-3.0) 1
• Women at moderate to high risk of recurrent VTE (single unprovoked VTE, pregnancy/estrogen-related VTE, or multiple unprovoked VTE) should receive antepartum prophylaxis with prophylactic or intermediate-dose LMWH 1
• Women with homozygous factor V Leiden or prothrombin 20210A mutation with positive family history for VTE should receive antepartum prophylaxis with prophylactic or intermediate-dose LMWH 1
• Women receiving long-term vitamin K antagonists should receive adjusted-dose LMWH or 75% of therapeutic dose LMWH throughout pregnancy 1

Moderate Risk - Require Postpartum Prophylaxis Only

• Women with thrombophilias (other than homozygous factor V Leiden or prothrombin 20210A mutation) and positive family history for VTE should receive postpartum prophylaxis but only antepartum clinical vigilance 1
• Women with homozygous factor V Leiden or prothrombin 20210A mutation without positive family history for VTE should receive postpartum prophylaxis but only antepartum clinical vigilance 1
• Women with low risk of recurrent VTE (single episode associated with transient risk factor not related to pregnancy or estrogen use) should receive clinical vigilance antepartum 1

Low Risk - Clinical Vigilance Only

• Women with thrombophilias (other than homozygous factor V Leiden or prothrombin 20210A mutation) without prior VTE or positive family history should receive antepartum and postpartum clinical vigilance only 1

Choice of Anticoagulant

• LMWH is strongly recommended over unfractionated heparin (UFH) for prevention and treatment of VTE in pregnant women 1
• Both LMWH and UFH are considered safe during pregnancy as they do not cross the placenta 2
• LMWH offers lower risk of heparin-induced thrombocytopenia compared to UFH 2
• Vitamin K antagonists are contraindicated during pregnancy due to potential teratogenicity 2
• Oral direct thrombin inhibitors and factor Xa inhibitors should be avoided during pregnancy 1

Special Considerations

Heparin-Induced Thrombocytopenia (HIT)

• For pregnant women who develop HIT, alternative anticoagulants such as argatroban or fondaparinux may be considered 3
• These alternatives should be used only when heparin products are contraindicated 4

Duration of Treatment

• For pregnant women with acute VTE, anticoagulation should continue for at least 6 weeks postpartum with a minimum total duration of 3 months 2
• For women with recurrent VTE or those on long-term anticoagulation, treatment should continue throughout pregnancy and postpartum 5

Delivery Considerations

• LMWH should be discontinued at least 24 hours prior to induction of labor, cesarean section, or expected time of neuraxial anesthesia 1
• Anticoagulation can be safely resumed postpartum, even during breastfeeding 1

Common Pitfalls to Avoid

• Failure to distinguish between thrombophilia types: Not all thrombophilias carry the same risk - homozygous factor V Leiden and prothrombin 20210A mutations carry higher risk than other thrombophilias 1
• Inappropriate use of vitamin K antagonists: These should be avoided during pregnancy due to teratogenic effects 2
• Inadequate duration of therapy: Postpartum prophylaxis should continue for at least 6 weeks 1
• Confusion between thrombophilia and thrombocytopenia: Thrombocytopenia (low platelet count) is a different condition that may require different management approaches 6

By following these guidelines, clinicians can appropriately manage pregnant patients with thrombophilia to minimize the risk of thrombotic events while ensuring maternal and fetal safety.