麻豆村

Clinicians rely on fetal heart rate to assess distress during labor, but it doesn鈥檛 reveal oxygen levels. New research from Carnegie Mellon introduces a noninvasive optical framework to estimate fetal oxygenation, offering a potential advance in monitoring fetal health during childbirth.

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During labor and delivery, clinicians rely largely on a single signal, the fetal heart rate, to assess whether a baby is in distress. While changes in heart rate can indicate potential problems, they do not directly reveal whether a fetus is receiving enough oxygen, a critical factor in healthy development. Despite decades of medical innovation, this limitation has remained largely unchanged since fetal heart rate monitoring became standard practice in the 1970s.

Biomedical engineers at 麻豆村 are working to address this gap. In a paper recently published in , 麻豆村 researchers, in collaboration with 听Raydiant Oximetry, outline a foundational optical framework designed to noninvasively estimate fetal oxygen saturation through the mother鈥檚 abdomen. This advance could eventually provide clinicians with a more complete picture of fetal well-being during labor.

鈥淭his work is a meaningful first step toward giving clinicians a more direct window into fetal oxygenation during labor, but further validation and development are still needed,鈥� shared Jingyi Wu, former biomedical engineering Ph.D. student and the study鈥檚 first author.

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Measuring oxygen in the blood is routine in modern medicine. Pulse oximeters, small devices that clip onto a finger, use light to estimate how much oxygen the blood is carrying, and billions of such measurements are taken every day. But applying this technology to a fetus is far more complex.

鈥淔rom a fundamental perspective, there are many reasons pulse oximetry shouldn鈥檛 work,鈥� explained Jana Kainerstorfer, professor of biomedical engineering. 鈥淭he fact that it does work on a finger is remarkable. Trying to make it work for the fetus is vastly more complicated.鈥�

In transabdominal fetal pulse oximetry, light must travel through multiple layers of tissue before reaching the fetus and returning to a detector on the surface of the abdomen. These layers include maternal fat, muscle, the uterine wall, amniotic fluid, and fetal tissue. Each layer alters the signal, and maternal and fetal physiological signals overlap, making it difficult to isolate information from the fetus alone.

To address this challenge, the researchers developed a multi-layer, self-calibrated algorithm that explicitly models how light propagates through maternal and fetal tissue.

鈥淭his work is really about understanding the physics of the problem,鈥� Kainerstorfer said. 鈥淲e wanted an analytical framework that explains how the signal is formed, rather than relying on large datasets to learn those relationships.鈥�

That approach differs from machine learning based methods, which typically require extensive training data from many subjects. Instead, the framework is designed to be generalizable and operates without external lookup tables or large calibration cohorts.

The team validated the approach using both simulations and in vivo experiments. Under optimal simulation conditions, the algorithm estimated fetal oxygen saturation with high accuracy. The researchers then tested the framework in non-human subjects, comparing transabdominal optical measurements with reference blood oxygen values. The results showed good agreement and demonstrated proof-of-concept feasibility beyond simulation alone.

The ability to directly measure fetal oxygenation could have significant implications for obstetric care. In the United States, Cesarean deliveries account for roughly one-third of all births, and many are performed out of concern for possible fetal distress. Without direct information about oxygen levels, clinical decision-making during labor often relies on incomplete data.

鈥淲hen a fetus is suspected to be hypoxic, care teams may have to act quickly without knowing the underlying cause,鈥� Kainerstorfer elaborated. 鈥淗eart rate changes can signal a problem, but they don鈥檛 tell you why it鈥檚 happening.鈥�

Although the application is new, the work fits closely with Kainerstorfer鈥檚 broader research in biomedical optics, which focuses on noninvasive ways to measure oxygenation and blood flow deep within tissue. Her lab has previously developed optical approaches for monitoring brain physiology, and similar challenges arise in other projects, including optical measurements in marine mammals.

鈥淎t the core, I鈥檓 interested in how oxygen, and the lack of it, affects the brain at all stages of life,鈥� concluded Kainerstorfer. 鈥淔rom a technology standpoint, the question is always the same, how do you measure physiology deep inside tissue you can鈥檛 directly access? Standard fetal monitoring has not fundamentally changed in decades. If we can provide clinicians with better information about fetal oxygenation, that would be a meaningful step forward for maternal and fetal care.鈥�

For media inquiries, please contact Sara Pecchia at pecchia@cmu.edu.