Icon Legend

This session is not in your schedule.

This session is in your schedule. Click again to remove it.

Presentation Icons

Additional registration fee required

Faculty have requested this content not be shared outside of the session

CME Credit Offered

Abstract Award

Recording available 2/16-5/2

AIUM Credit

Foundation Awardee

Poster Icons

Abstract Award

Foundation Awardee

Poster Session 3

Category: Epidemiology

Poster Session 3

(755) Beyond ICD Codes and Quantitative Blood Loss: Evidence of Continued Increase in Postpartum Hemorrhage (2016-2025)

Thursday, February 12, 2026

10:30 AM - 12:00 PM

Submitting Author and Presenting Author(s)

Chloe Stanwyck, MD, MS (she/her/hers)

Obstetric Anesthesiology Fellow
Stanford University
Menlo Park, California, United States

Coauthor(s)

NG

Nan Guo, PhD

Stanford University School of Medicine
Stanford, California, United States
Kay I. Daniels, MD

Clinical Professor Obstetrics and Gynecology CoDirector of Disaster Planning for the Johnson Center for Pregnancy and Newborn Services
Stanford University School of Medicine
Stanford, California, United States
KF

Kelly Fedoruk, MD

Stanford University School of Medicine
Stanford, California, United States
BC

Brendan Carvalho, MD

Professor
Stanford University Healthcare
Palo Alto, California, United States
JA

Jessica Ansari

Stanford University
Stanford University, California, United States

Objective:
Epidemiologic studies of postpartum hemorrhage (PPH) rates are based on retrievable data elements (ICD codes, blood loss quantification, and transfusion records) that may be impacted by inaccurate documentation and coding errors. We aimed to assess an objective, laboratory‑based indicator of PPH - a ≥ 3 g/dL decline in hemoglobin - and compared trends in hemoglobin-based PPH with PPH defined by blood loss, ICD codes, red blood cell (RBC) transfusion, or discharge summary mentions.

Study Design:
We examined all deliveries at a tertiary care hospital from 1/1/2016 - 4/30/2025, excluding antenatally diagnosed placenta accreta. The primary outcome was ≥3 g/dL drop in hemoglobin. Secondary outcomes were quantitative or estimated blood loss (QBL or EBL) > 1000 mL, PPH-related ICD codes, RBC transfusion, and mention of clinically significant PPH in the discharge summary as identified by a large language model (GPT-4.1). Yearly prevalence was plotted and annual change estimated with modified-Poisson regression (log link, robust standard errors), treating calendar year as a continuous predictor.

Results:
Among 42,373 deliveries, PPH incidence rose steadily by every definition over the study period (Figure 1). Fall in hemoglobin increased by 4% per year, corresponding to a 45% higher risk in 2025 vs. 2016 (RR 1.45, 95 % CI 1.33-1.57; Table 1). Secondary outcomes showed even larger increases (RR [95 % CI]): QBL > 1000 mL, 1.94 (1.77–2.13); transfusion, 2.70 (2.18–3.35); ICD-coded PPH, 2.81 (2.58–3.06); and LLM-identified PPH in discharge summaries, 2.24 (2.02–2.48).

Conclusion:
This contemporary investigation revealed that PPH incidence steadily increased by every definition examined, including a ≥ 3 g/dL hemoglobin drop. The 45% relative increase in this laboratory‑based, objective outcome demonstrates that increases in PPH cannot be fully attributed to changes in measurement, coding, or transfusion practice. These findings underscore the need to define patient and system factors that underlie the continued rise in PPH. In the meantime, enhanced prevention and real-time PPH surveillance are imperative.