The following article features coverage from the 61st American Society of Hematology Annual Meeting and Exposition. Click here to read more of Hematology Advisor’s conference coverage.

Women with factor XI (FXI) deficiency may be at increased risk for postpartum hemorrhage if they undergo cesarean delivery, according to research presented at the 61st American Society of Hematology (ASH) Annual Meeting in Orlando, Florida.

It has become increasingly common for direct-to-consumer genetic testing companies to screen for FXI mutations, said presenter Thomas Bogue, BS, of Beth Israel Deaconess Medical Center in Boston, Massachusetts. As a result, there is an influx of “patients who have never experienced a bleed but who have now discovered they have mild FXI deficiency,” and there is a need to consider this risk when these patients undergo surgery.

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To assess postpartum hemorrhage risk in women with mild FXI deficiency, researchers enrolled 200 patients who underwent delivery between 2016 and 2018 in this matched, retrospective, case-control, single-institution analysis. There were 71 deliveries in the FXI deficiency cohort (40 patients), of which 45 were vaginal and 26 were cesarean. In the control cohort (160 patients), there were 200 deliveries, of which 125 were vaginal and 75 were cesarean. Postpartum hemorrhage was defined as estimated blood loss of at least 1000 mL or blood loss accompanied hypovolemia symptoms within 24 hours following delivery.

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In both cohorts, median estimated blood loss for vaginal deliveries was 300 mL and median estimated blood loss for cesarean deliveries was 800 mL. Among patients undergoing vaginal delivery, postpartum hemorrhage occurred after no deliveries in the FXI deficiency cohort and after 1 delivery in the control cohort. Conversely, among patients undergoing cesarean delivery, postpartum hemorrhage occurred in 10 deliveries (38.5%) of deliveries in the FXI deficiency cohort and in 14 deliveries (18.7%) in the control cohort (odds ratio, 2.73; 95% CI, 1.02-7.26; P =.041).

The 26 cesarean deliveries in women with mild FXI deficiency were further stratified by history of bleeding; 16 deliveries were to women with no history of bleeding, while 10 deliveries were to women with at least 1 prior bleed. Women with mild FXI deficiency who had a history of bleeding were significantly more likely to experience postpartum hemorrhage after cesearen delivery compared with women with mild FXI defiency and no bleeding history (70.0% vs 18.8%) as well as women in the control cohort (70.0% vs 18.7%; P =.0017).

Red blood cell transfusions were necessary for 3 patients in the control cohort and no patients in the FXI deficiency cohort. FXI level itself was not found to be a predictor of postpartum hemorrhage outcomes.

Only 2 patients who experienced postpartum hemorrhage also received prophylaxis, “supporting the role of prophylactic measures in this high-risk group,” the researchers noted.

Disclosures: Some authors have declared affiliations with the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


  1. Bogue T, James S, Zwicker JI. Postpartum hemorrhage outcomes in women with mild factor XI deficiency. Oral presentation at: 61st ASH Annual Meeting and Exposition; December 7-10, 2019; Orlando, FL. Abstract 629.