PIPages
Labs

Bernard Choi

University of California-Irvine, CA·Biomedical Engineering

Severe bleeding after childbirth, called postpartum hemorrhage, is the leading cause of death among pregnant women. The danger is not just the bleeding but how quietly it progresses: the body compensates for lost blood volume so effectively that a woman can lose as much as 30% of her blood while heart rate and blood pressure still read as normal.

Fields

Biomedical Engineering

Medicine & Clinical Research

Engineering

Topics

postpartum hemorrhage

maternal health

wearable sensors

Grants
1 known grant, through May 2028

What they work on

  1. Complete and validate an initial wearable prototype that integrates a MEMS-based blood pressure sensor with a compensatory reserve index sensor measuring how much circulatory reserve remains before collapse.
  2. Define design requirements for the refined wearable prototype by shadowing clinicians, conducting interviews, and running focus groups in obstetric care settings.
  3. Test the refined MOMS prototype against a validated lower-body negative pressure protocol that simulates blood loss in volunteers, assessing whether waveform monitoring detects hypovolemia earlier than commercial monitors.
  4. Build multimodal machine learning algorithms that fuse the device's several physiological waveform streams to predict postpartum hemorrhage, with explainability analysis so clinicians can interpret alerts.

More about the research

By the time blood pressure finally drops, circulatory collapse may be minutes away and the window for a life-saving intervention has often closed. The core problem is therefore one of detection — standard vital signs, read as single numbers, are not actionable early enough.

Why it matters

Postpartum hemorrhage is a leading cause of maternal death, and current monitors often raise the alarm only when circulatory collapse is already imminent. A wearable that flags significant blood loss earlier, during the compensated phase when standard vital signs still look normal, could give clinicians time to intervene and may improve survival for new mothers in hospital and in ambulatory postpartum care.

Known grants

From NIH and NSF research grants. Labs often have other funding we can't see.

Maternal Obstetric Monitoring System (MOMS): a Postpartum Hemorrhage (PPH) Wearable Monitor

NIH · Sep 2025 – May 2028

Closest labs

Alexander Friedman

Columbia University, NY·Medicine & Clinical Research

Measure how closely care for severe hypertension, obstetric hemorrhage, sepsis and abnormal maternal vital signs follows safety bundle recommendations, using EHR data from eight consortium hospitals.

Yasser El-Sayed

Stanford University, CA·Medicine & Clinical Research

Adapt and implement an anemia prevention toolkit, previously piloted in California, for rural prenatal clinics and Federally Qualified Health Centers (community clinics for underserved patients) in Alabama.

Maxime Cannesson

University of California-Los Angeles, CA·Medicine & Clinical Research

Develop machine learning models that predict major complications after surgery by combining electronic health record data, high-fidelity physiological waveform features, and genomic data.

The school

University of California-Irvine: 46 labs on PI Pages, $645M a year on research, 524 research doctorates a year.

More about University of California-Irvine

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