American Society of Hirudotherapy

American Society of Hematology 2018 guidelines for management of venous thromboembolism: venous thromboembolism in the context of pregnancy.

Research article published in Blood advances (2018)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Practice guidelineDrug DevelopmentSalivary PharmacologyBates et al. · Blood advances, 2018

Abstract

BACKGROUND: Venous thromboembolism (VTE) complicates ∼1.2 of every 1000 deliveries. Despite these low absolute risks, pregnancy-associated VTE is a leading cause of maternal morbidity and mortality. OBJECTIVE: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians and others in decisions about the prevention and management of pregnancy-associated VTE. METHODS: ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations. RESULTS: The panel agreed on 31 recommendations related to the treatment of VTE and superficial vein thrombosis, diagnosis of VTE, and thrombosis prophylaxis. CONCLUSIONS: There was a strong recommendation for low-molecular-weight heparin (LWMH) over unfractionated heparin for acute VTE. Most recommendations were conditional, including those for either twice-per-day or once-per-day LMWH dosing for the treatment of acute VTE and initial outpatient therapy over hospital admission with low-risk acute VTE, as well as against routine anti-factor Xa (FXa) monitoring to guide dosing with LMWH for VTE treatment. There was a strong recommendation (low certainty in evidence) for antepartum anticoagulant prophylaxis with a history of unprovoked or hormonally associated VTE and a conditional recommendation against antepartum anticoagulant prophylaxis with prior VTE associated with a resolved nonhormonal provoking risk factor.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal ArticlePractice Guideline
Indexed MeSH termsAdministration, OralAnticoagulantsBreast FeedingEvidence-Based MedicineFemaleFibrinolytic AgentsHeparin, Low-Molecular-WeightHumansInfantInfant, NewbornPregnancyVenous Thromboembolism

Summary

Venous thromboembolism (VTE) complicates ∼1.2 of every 1000 deliveries. Despite these low absolute risks, pregnancy-associated VTE is a leading cause of maternal morbidity and mortality.

Why This Matters for Hirudotherapy

These GRADE-based American Society of Hematology 2018 guidelines issued 31 recommendations on preventing and treating pregnancy-associated venous thromboembolism, including a strong recommendation for low-molecular-weight heparin over unfractionated heparin for acute VTE and largely conditional recommendations on dosing, outpatient treatment, and antepartum prophylaxis. The relevance to hirudotherapy is contextual and cautionary: it documents how carefully anticoagulation is calibrated in a bleeding-sensitive population, underscoring that the anticoagulant action of the leech secretome would demand comparable risk assessment and that pregnancy is a setting where any added bleeding risk is weighed heavily. Caveat: this is a systematic-review-based clinical guideline on pharmacologic anticoagulation in pregnancy with no data on or reference to leech therapy, and most recommendations are conditional with low-to-moderate certainty.

Citation

American Society of Hematology 2018 guidelines for management of venous thromboembolism: venous thromboembolism in the context of pregnancy.

Bates et al. · Blood advances, 2018

Added to ASH library: May 28, 2026 · Site last updated: June 18, 2026

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