Human milk is the ideal source of nutrition for infants. Most health organizations recommend direct breastfeeding from the first hour of life, extending throughout the first and second year. However, uncertainties regarding the volumes of milk ingested by the infant contribute to suboptimal rates of breastfeeding. Here we introduce a compact and unobtrusive device that gently interfaces to the breast via four electrodes and accurately measures expressed milk volume during breastfeeding through changes in the alternating current impedance. The data pass wirelessly to a smartphone continuously throughout each breastfeeding session for real-time graphical display. Comprehensive experimental and computational results establish the operating principles and guide engineering choices for optimized performance. Evaluations with 12 breastfeeding mothers over periods of as long as 17 weeks in the neonatal intensive care unit and in home settings illustrate the practical utility of this technology in addressing a critically important unmet need in maternal and neonatal care.
This work was supported by the Querrey Simpson Institute for Bioelectronics at Northwestern University. S.O. acknowledges funding from a National Research Foundation of Korea (NRF) grant (2021R1C1C2010180) funded by the Korea government (MSIT), and the DHA SBIR Phase II award (W81XWH22C0106). R.A. acknowledges support from the ASME\\u2014Applied Mechanics Division Haythornthwaite Foundation Research Initiation Grant. J.-Y.Y. acknowledges funding from the Basic Research Laboratory (BRL) Project of National Research Foundation (RS-2024-00406674) funded by the Ministry of Science and ICT of Korea, as well as the Technology Innovation Program (RS-2024-00443121) funded by the Ministry of Trade Industry and Energy (MOTIE, Korea).
