— A South Korea–U.S. joint research team has developed the world’s first clinically validated wearable sensor capable of accurately measuring the amount of breast milk consumed by infants during nursing in real time—potentially transforming neonatal care and easing anxiety for new mothers.

The study, published May 14 in the journal Nature Biomedical Engineering, was led by Professors Kim Ji-hye (Ajou University), Oh Se-yong (Hanyang University), Yoo Jae-young (Sungkyunkwan University), and John Rogers (Northwestern University).

While breastfeeding is widely recommended for its health benefits, quantifying milk intake has long remained a challenge. Existing methods require comparing an infant’s weight before and after feeding or expressing milk in advance—both of which are cumbersome and lack real-time precision.

The newly developed sensor solves this with bio-impedance technology, commonly used in body composition analysis. Two small adhesive pads are placed above and below the breast, sending a harmless electrical current through the tissue. By tracking voltage changes as milk volume decreases during feeding, the system calculates how much milk is consumed.

Using anatomical modeling and simulations, the team optimized sensor placement and calibration. The result is a personalized, noninvasive device that syncs with a smartphone app and requires just one initial calibration via a breast pump to function accurately.

In field tests involving 12 breastfeeding mothers in both hospital and home settings over periods of up to 17 weeks, the sensor’s readings closely matched results from both expressed milk volumes and traditional infant weighing methods. Users also reported no discomfort wearing the device.

“This is the first time a technology has clinically and quantitatively verified real-time breastfeeding data and made it accessible,” said Professor Kim. “It reduces the uncertainty and stress many mothers face and offers healthcare providers a reliable tool for infant nutrition monitoring.”

The team has filed patents and is exploring commercial applications, including integrating the sensor into nursing garments. Future upgrades aim to detect changes in milk quality, fat content, and maternal milk supply.

The researchers are in talks with breast pump manufacturers to commercialize the sensor. “This technology could reduce the self-doubt that leads some mothers to abandon breastfeeding prematurely,” Kim added. “Ultimately, it contributes to healthier babies, mothers—and society.”

M. H. Lee ([email protected])