Postpartum hemorrhage (PPH), defined as blood loss greater than or equal to 1,000 mL, or blood loss accompanied by signs of hypovolemia, is a leading cause of severe maternal morbidity and may necessitate massive transfusion.1 While balanced component therapy is standard, low-titer group O-positive whole blood (LTOpWB) has gained attention for hemorrhage resuscitation because it simplifies logistics and reduces donor exposure. Early obstetric experience supports the feasibility of whole blood for PPH, including early institutional implementation,2 use in placenta accreta spectrum disorder (PASD) programs,3 and administration during prehospital transport.4 However, obstetric data remain limited, and additional studies are needed to determine whether LTOpWB provides outcomes comparable to conventional component therapy in this population. We conducted a single-center retrospective cohort study evaluating obstetric patients receiving massive transfusion before and after institutional implementation of LTOpWB. Patients treated with component therapy (2016–2018) were compared to those treated after LTOpWB incorporation into massive transfusion strategies (2020–2024), excluding the 2019 transition year. Massive transfusion was defined as more than 4 units in 1 h or more than 10 units in 24 h.1 During the latter period, our institution became a regional referral center for PASD, and our institutional policy shifted to favor LTOpWB for PPH in PASD deliveries.3 These changes are a major driver of baseline cohort differences and likely account for the higher proportion of PASD in the LTOpWB group (62% vs. 38%; Table 1). We compared transfusion burden and selected outcomes between the two strategies. Using published methods for unit volume conversions,5 we quantified total blood product volume and anticoagulant/preservative exposure. As shown in Table 2, the LTOpWB group received significantly fewer blood product units (10.6 vs. 20.8 units, p = .04) with comparable median total transfused volume (3227 mL vs. 3244 mL, p = .59), supporting feasibility with similar resuscitation volume. Notably, the LTOpWB group had significantly less anticoagulant/preservative exposure (567 mL vs. 900 mL, p < .0001) and a lower observed proportion of disseminated intravascular coagulation (DIC) (18% vs. 36%, p = .03). Mean donor exposure was also reduced in the LTOpWB group (13.14 vs. 27.96; k = 6 for pooled platelets); although not statistically significant (p = .06), the approximately two-fold reduction in donor exposures may be clinically relevant, given the importance of minimizing alloimmunization and transfusion-related risks in obstetrics. Many outcomes, such as Rh-negative status and maternal death, were rare in both groups, limiting inference. Intensive care unit (ICU) admission and hysterectomy were more frequent in the LTOpWB cohort; however, these outcomes are strongly confounded by the higher prevalence of PASD, which at our institution is managed exclusively by planned cesarean hysterectomy. In summary, following implementation during a period marked by a major institutional shift toward PASD referral care, LTOpWB was feasible and demonstrated similar total transfused volumes compared with component therapy for obstetric hemorrhage resuscitation. Additionally, LTOpWB was associated with lower anticoagulant/preservative exposure and a lower observed incidence of DIC. Larger multicenter studies with risk adjustment and PASD-stratified analyses are needed to confirm these findings and determine whether reduced additive exposure contributes to improved coagulation outcomes in obstetrics. The authors have disclosed no conflicts of interest. The data that support the findings of this study are available from the corresponding author upon reasonable request.
Ross et al. (Thu,) studied this question.