How Women Do It All: Rheometry, flow visualization, and computational modeling of breastmilk expression

Breastmilk is the ideal nutrition for infants. While 80% of U.S. infants begin breastfeeding, fewer than 30% continue by six months. Beyond societal barriers, women can experience clogged ducts, pain, and irregular milk expression. Clinical studies provide valuable insights into physiological contributors; however, there is a clear gap in our understanding of how physical factors, such as fluid properties, limit or facilitate milk expression.

To quantify shear-rate dependent viscosity and assess key transport characteristics, we performed rheometry on fresh milk samples. A transparent breastmilk simulant was developed to enable reproducible flow visualization in an anatomically accurate physical breast model. Experimental results were extended with numerical simulations incorporating realistic biomechanical force inputs to evaluate the relationship between breastmilk rheology and the forces involved in breastfeeding. This work establishes a mechanistic framework for milk transport and provides a data-driven approach to addressing common issues that impede breastfeeding.