Changes in R0/R∞ ratio and membrane capacitance are associated with milk removal from the breast

Perceived low milk supply is a common reason for introducing supplementary feeds, which in turn serves to further diminish the milk supply. Current methods of measuring milk production and milk transfer from the breast to the infant are inaccessible to the mothers. There is a need for an inexpensive, portable device to enable mothers to measure milk transfer to either confirm their milk production is adequate or identify breastfeeding issues early. The aim of this study was to examine changes in bioimpedance spectroscopy associated with milk removal from the human lactating breast using an electric breast pump. Thirty lactating women participated in 2 research sessions performed in random order over 2 weeks. Milk flow rate and volume were measured during pumping. All mothers completed 24-hour milk profiles. Breasts were monitored using bioimpedance spectroscopy. Analysis was performed using linear mixed effects models to investigate the relationship between both proportional change in membrane capacitance (C(m)) and R0/R∞ with milk removal. There was an inverse relationship between R0/R∞ and milk removed (p<0.001). A positive relationship was also observed between C(m) and both volume of milk removed (P<0.001) and percentage of available milk removed (p<0.001). This study has shown that changes in bioimpedance are related to the volume of milk removed from the breast during pumping. This modality may hold promise for the measurement of the effectiveness of the breastfeeding infant in removing milk from the breast.