Abstract Number: LPB0095
Meeting: ISTH 2021 Congress
Background: Pregnant women are at higher risk of venous thromboembolism (VTE), which represents an important cause of maternal morbidity and mortality. Estimates of bleeding associated with anticoagulation in patients with VTE during pregnancy are not well described.
Aims: To describe the frequency of major bleeding and postpartum hemorrhage in women receiving therapeutic anticoagulation for pregnancy associated VTE by means of a systematic review of the literature.
Methods: An electronic search was conducted from database inception to January 21, 2021 using Medline, Embase, Scopus and Web of Science. Key words related to anticoagulation including “heparin”, “low molecular weight heparin” and key words related to bleeding including “postpartum”, “antepartum” or “peripartum” and “hemorrhage” were used. There was no language or geographic location restriction. Included studies (1) described women treated for an acute pregnancy associated VTE, (2) receiving therapeutic anticoagulation and (3) a defined bleeding outcome was reported. Two independent reviewers extracted the data using predefined criteria, and clinical bleeding outcomes were collected.
Results: Of 1636 deduplicated references identified, seven studies including a total of 2338 women receiving therapeutic anticoagulation for VTE were included. Four studies were retrospective. Bleeding definitions varied between studies. Frequency of bleeding ranged between 1.41% and 8.40% and postpartum hemorrhage between 1.90% and 30.0%. Three of the eight studies included control groups, two of which found no significant difference in the risk of bleeding between groups, while the third found a significantly increased bleeding risk.
|Study||Study Design||Population Size (n)||Control Group (n)||Bleeding Definition||Bleeding Result|
|Blanco-Molina et al.||Prospective cohort||136||NA||Major bleeding: overt and associated with decrease in hemoglobin >20 g/L, >2 units of blood or retroperitoneal/intracranial bleeds.||4/136 (2.9%) had major bleeding.|
|Chan et al.||Retrospective cohort||60||NA||ISTH definition of major bleeding*.||Of the 6 bleeding events (6/60, 10%), 3/60 (5%, 95% CI 1-14%) had major bleeding.|
|Chen et al.||Systematic review and meta-analysis||746||3296**||Variable.||No difference in incidence of antepartum bleeding between groups (OR 1.08 95% CI 0.84-1.40).|
|Côté-Poirier et al.||Retrospective cohort||232||NA||Major hemorrhagic complication: requiring surgery, hospital readmission, admission to ICU, red blood cell transfusion or fluid resuscitation of >1L or crystalloids (for bleeding concern).||Major hemorrhagic complication occurred in 7/83 for CS (8.4%, 95% CI 3.5-16.6) and 9/149 for VD (6.0%, 95% CI 2.8-11.1).|
|Knol et al.||Retrospective cohort||88||352||VD: PPH >500 mL, severe PPH >1000 mL
CS: PPH >1000 mL
|In VD, PPH occurred in 30% vs. 18% in treatment vs. control group (OR 1.19, 95% CI 1.1-3.5, p=0.029) and risk of severe PPH 5.6% vs. 5.0% (OR 1.1, 95% CI 0.4-3.6). In CS, risk of PPH was 12% vs. 4% (OR 2.9, 95 CI 0.5-19.4).|
|Romualdi et al.||Systematic review and meta-analysis||981||NA||Variable.||The weight mean incidence of major bleeding was 1.41% (95% CI 0.60-2.41%) antenatally and 1.90% (95% CI 0.80-3.60%) during the first 24h after delivery.|
|Roshani et al.||Retrospective cohort||95||524||PPH > 500 mL, severe PPH > 1000 mL||PPH occurred in 18% in treatment group vs. 22% in controls (RR for PPH 0.8, 95% CI 0.5-1.4). Incidence of severe PPH was the same in both group (6%) (RR 1.2 95% CI 0.5-2.9).|
|*Major bleeding ISTH definition: fatal, in critical area (intracranial, intra-spinal, retroperitoneal), bleeding causing drop > 20 g/L in hemoglobin level or transfusion of 2 or more units of blood.
**The control group received prophylactic anticoagulation.
Abbreviations: NA= non-available, ISTH = International Society on Thrombosis and Haemostasis, CRNMB = clinically relevant non-major bleeding, CI = confidence interval, OR = odds ratio, ICU = intensive care unit, CS = cesarian delivery, VD = vaginal delivery, PPH = postpartum hemorrhage, RR = relative risk.
Conclusions: Among pregnant women anticoagulated for VTE, reported bleeding frequency is variable. The ability to make inference is limited by the observational nature of studies, small number of patients and heterogeneity of bleeding definitions. Large scale prospective studies with standard bleeding definitions are needed to provide accurate bleeding estimates and anticipate the healthcare needs of pregnant women with VTE.
To cite this abstract in AMA style:Simard C, Malhamé I, Douros A, Filion KB, Tagalakis V. Bleeding Complications in Women with Venous Thromboembolism during Pregnancy: A Systematic Review of the Literature [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 1). https://abstracts.isth.org/abstract/bleeding-complications-in-women-with-venous-thromboembolism-during-pregnancy-a-systematic-review-of-the-literature/. Accessed September 24, 2021.
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