Need for Antepartum Thromboprophylaxis in Pregnant Women With One Prior Episode of Venous Thromboembolism (VTE)

Hamilton Health Sciences Corporation203 enrolled

Overview

Pregnant women with a prior history of venous thromboembolism (VTE) are at increased risk of recurrent VTE. Current guidelines assessing the role of prophylaxis in pregnant women with prior VTE are based primarily on expert opinion and the optimal clinical management strategy remains unclear. This multicentre, prospective cohort study aims to test the following hypotheses: 1. Antepartum prophylaxis with fixed-dose low molecular-weight heparin (LMWH) is safe, convenient and associated with an acceptably low risk of recurrent VTE in women with a single prior episode of VTE that was either unprovoked or associated with a minor transient risk factor. (Moderate risk cohort) 2. Withholding antepartum prophylaxis is safe (recurrence risk \<1%) in pregnant women with a single prior episode of VTE provoked by a major transient risk factor. (Low risk cohort) All study patients will receive 6 weeks of postpartum prophylaxis.

Study Type

OBSERVATIONAL

Enrollment

203

Conditions

Venous Thromboembolism Deep Vein Thrombosis Pulmonary Embolism

Eligibility

Sex: FEMALEMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Confirmed pregnancy (positive serum or urine) * At least 18 years of age * History of one prior episode of VTE consisting of DVT (diagnosed by compression ultrasonography \[CUS\] or venography) and/or PE (diagnosed by ventilation-perfusion \[V/Q\] lung scintigraphy, computed tomographic pulmonary angiography \[CTPA\], or traditional pulmonary angiography) Exclusion Criteria: * Ongoing need for therapeutic anticoagulation for prevention or treatment of cardioembolic stroke * Known high-risk thrombophilia (specifically antithrombin deficiency, protein S deficiency, protein C deficiency, homozygosity for the factor V Leiden or prothrombin G20210A mutations, antiphospholipid antibody or compound abnormalities) * VTE within 3 months of the current pregnancy * Clinical risk factor for initial episode of VTE, if present, not resolved (excluding pregnancy) * Known contraindication to anticoagulation (including active, uncontrolled bleeding or major bleed within the previous 4 weeks) * For patients with prior unprovoked VTE, contraindication to LMWH (including allergy, HIT, impaired renal function, osteoporosis) * Geographic or social factors precluding follow-up * Inability or unwillingness to provide informed consent

Outcomes

Primary Outcomes

Symptomatic venous thromboembolism

Symptomatic objectively confirmed recurrent VTE, including proximal DVT, non-fatal PE, and fatal PE during antepartum period

Time frame: antepartum period (expected average 7 months)

Secondary Outcomes

Symptomatic recurrent venous thromboembolism

Symptomatic recurrent VTE antepartum and within first 3 months postpartum

Time frame: antepartum period (expected average 7 months) and first 3 months postpartum

Symptomatic recurrent pulmonary embolism

Symptomatic objectively confirmed recurrent PE antepartum and within first 3 months postpartum

Time frame: antepartum period (expected average 7 months) and first 3 months postpartum

Thrombocytopenia or heparin-induced thrombocytopenia (HIT)

Thrombocytopenia or HIT during antepartum period

Time frame: antepartum period (expected average 7 months)

Symptomatic osteoporosis

Symptomatic osteoporosis antepartum and within first 3 months postpartum

Time frame: antepartum period (expected average 7 months) and first 3 months postpartum

Other complications

Other complications sufficient to stop treatment (e.g., local and systemic reactions) antepartum and within first 3 months postpartum

Time frame: antepartum (expected average 7 months) and within first 3 months postpartum

Pregnancy complications and outcomes

Pregnancy complications and outcomes including fetal death, pre-eclampsia, toxemia, intrauterine growth restriction, prematurity during antepartum period

Time frame: antepartum period (expected average 7 months)

Fetal anomalies

Time frame: antepartum (expected average 7 months) and during first 3 months postpartum

Major and minor bleeding

Time frame: antepartum (expected average 7 months)

Need for Antepartum Thromboprophylaxis in Pregnant Women With One Prior Episode of Venous Thromboembolism (VTE)

Overview

Conditions

Eligibility

Locations (2)

Outcomes

Primary Outcomes

Secondary Outcomes

Central Contacts