Hemoglobin Change after Red Blood Cell Transfusion for Postpartum Anemia: Secondary Analysis of a Randomized, Controlled Trial

Abstract

Objective We aimed to describe hemoglobin (Hb) change after transfusion in the nonacute postpartum anemic population in order to provide clinicians with appropriate expectations regarding Hb rise posttransfusion. Study Design We performed a secondary analysis of a randomized controlled trial comparing initial transfusion with 1 unit of packed red blood cells (pRBCs) to 2 units pRBCs for postpartum women requiring nonacute transfusion (n = 66). Inclusion criteria were: age 18 years and older, Hb level either <7 g/dL or >7 g/dL with signs or symptoms of anemia, and > 6 hours postpartum without contraindication to transfusion. Hb assessment was performed 4 to 6 hours after initial transfusion. Hb change (ΔHb) was calculated as posttransfusion Hb minus randomization Hb. Our primary goal was to describe mean ΔHb per pRBC transfused at the 4- to 6-hour posttransfusion blood count. We also compared ΔHb per pRBC transfused by number of units transfused, body mass index (BMI), and symptoms (dizziness and/or fatigue) at time of posttransfusion assessment. Results Participants were mean age 29, mean BMI of 27, and over 70% self-identified as black, 12% identified as white, and 9% as Asian race. Mean Hb prior to transfusion was 6.9 ± 0.6 g/dL. Mean ΔHb per pRBC transfused was 0.9 ± 0.4g/dL. There was no difference in ΔHb per pRBC by BMI category (normal weight < 25 kg/m2: 1.1 ± 0.2 g/dL; overweight 25–29.9 kg/m2: 0.9 ± 0.5 g/dL; obese ≥ 30 kg/m2: 0.9 ± 0.5 g/dL; p = 0.12). Finally, there was also no significant difference in ΔHb per pRBC by whether or not symptoms of anemia persisted after initial transfusion (1.0 ± 0.7 vs. 0.9 ± 0.4 g/dL, p = 0.39). Conclusion Our data supports the classically accepted rise in Hb after pRBC of approximately 1 g/dL, regardless of BMI category or anemia symptomatology. The study population includes patients at highest risk of postpartum anemia. The results of our study provide important information for clinicians caring for postpartum patients with nonacute anemia. Key Points