2026 FSA Podium and Poster Abstracts

Background: Postpartum hemorrhage (PPH) remains a leading cause of maternal morbidity and mortality worldwide and is the most common indication for peripartum blood transfusion in the United States. In the United States and other high-resource countries, PPH rates and associated transfusion requirements have increased over recent decades. Antepartum anemia exacerbates this burden, as it reduces physiologic reserve for blood loss and lowers allowable blood loss thresholds before transfusion is needed. Anemia during pregnancy affects approximately one-third of women globally, with iron deficiency as the primary cause, and is one of the most frequently cited modifiable risk factors for PPH. The American College of Obstetricians and Gynecologists (ACOG) recognizes anemia as an important contributor to hemorrhagic complications as it impairs oxygen delivery to the myometrium, reduces tolerance for blood loss, and may exacerbate coagulopathy. Therefore, this study aimed to examine the association between severity of anemia and PPH rates.

Study Design and Methods: This institutional review board approved retrospective cohort study (IRB 20220290) reviewed birth logs and electronic medical records of all women who delivered at Jackson Memorial Hospital, a large urban safety-net hospital in Miami, Florida, from March 1, 2024, to February 28, 2025. Patients without an admission hemoglobin value or quantitative blood loss (QBL) measurement were excluded. PPH was defined as a QBL measurement of ≥1000 mL regardless of delivery mode, in accordance with ACOG guidelines. Admission hemoglobin (g/dL) was the last value obtained on admission to labor and delivery and was categorized in 1-g/dL increments. Blood loss was measured using a standardized institutional QBL protocol. Demographic and clinical data (including age, race/ethnicity, gestational age, delivery type) were extracted from electronic medical records. The proportion of PPH in each hemoglobin category was calculated. Fisher exact test was performed to assess overall association between hemoglobin categories and PPH. P < .05 was considered significant. Analyses were performed using R (version 4.5.1) via RStudio.

Results: Of 4,713 deliveries during the study period, 4635 (98.4%) had both an admission hemoglobin and QBL measurement available and were included in the analysis. Demographic characteristics of the cohort were summarized. The median hemoglobin on admission was 11.5 g/dL (IQR 10.6 – 12.4 g/dL). 32.7% of the cohort was anemic on admission. Rates of postpartum hemorrhage by admission hemoglobin category are presented in Table 1.

Discussion: The important finding of this study is that a relationship between admission hemoglobin concentration and PPH was observed. For every 1 g/dL decrement in hemoglobin below 11 g/dL, the absolute risk of PPH rose progressively. At a hemoglobin of <8 g/dL, women were more than twice as likely to experience a PPH compared to non-anemic women (≥11 g/dL). Strengths of this analysis include the large sample size, near-complete capture of admission hemoglobin values, use of quantitative blood loss, and a diverse, high-risk population. Limitations include the retrospective single-center design and potential residual confounding (e.g., by cause of anemia or comorbid conditions). In conclusion, increasing severity of admission anemia is strongly associated with higher rates of postpartum hemorrhage.