Barts Research Centre for Women's Health, Queen Mary University of London, UK; Barts Health, NHS Trust, London, UK. Barts Health, NHS Trust, London, UK; Wolfson Institute, Queen Mary University of London, UK. Barts Research Centre for Women's Health, Queen Mary University of London, UK. NHS Blood and Transplant, UK; Radcliffe Department of Medicine, University of Oxford, UK; Blizard Institute, Queen Mary University of London, UK. Barts Health, NHS Trust, London, UK; NHS Blood and Transplant, UK; Radcliffe Department of Medicine, University of Oxford, UK; Blizard Institute, Queen Mary University of London, UK. Electronic address: email@example.com.
Fibrinogen levels drop early in postpartum hemorrhage (PPH), and low fibrinogen levels predict outcomes. There is increasing interest in replacing fibrinogen early in severe PPH and this systematic review's aim was to assess if early fibrinogen replacement therapy improves outcomes in severe PPH. We searched the following databases from inception to June 2019: CDSR and CENTRAL (The Cochrane Library), MEDLINE,
Embase, CINAHL, PubMed, Transfusion Evidence Library, LILACS, Web of Science Conference Proceedings Citation Index-Science, ClinicalTrials.gov and the WHO International Clinical Trials Registry Portal. We included randomized (RCT) and well-designed controlled observational studies where fibrinogen replacement therapy was given early (within 90 minutes of bleeding) compared with standard protocol in pregnant women > 24 weeks' gestation who developed PPH, defined as estimated blood loss ≥500 mL up to 24 hours post-delivery. Two independent reviewers extracted and reviewed the data on the primary outcome of allogeneic blood transfusion at 24 hours after intervention and secondary outcomes including all-cause mortality, rate of thrombosis, and the need for surgical and non-surgical interventions. We identified 5 eligible studies: 2 completed (total of 299 women) RCTs comparing fibrinogen concentrate with placebo, and 3 ongoing RCTs. There was no completed study assessing cryoprecipitate transfusion. There was variation of: timings of intervention administration; severity of PPH; fibrinogen doses and use of tranexamic acid. There was insufficient evidence that early administration of fibrinogen in PPH reduces the need for allogeneic blood transfusion at 24 hours (risk ratio 0.83 (95% CI 0.54-1.26), P = 0.38) (2 trials, 299 participants) or improves other outcomes. Both studies were underpowered to answer our outcomes. There is a lack of evidence that early fibrinogen replacement therapy improves outcomes in PPH. Future studies are needed to address this, underpinned by data on the optimal fibrinogen dose, protocol-driven approaches versus targeted therapy, and cost-effectiveness of cryoprecipitate versus fibrinogen concentrate therapy in PPH.