Abstract
Breast massages performed by midwives or breast pumps are used in breast care for lactating women. However, the mechanical effects of a load exerted on the breasts remain unclear. Therefore, we prepared three-dimensional models for breasts, fingers (including thumbs), and a breast pump, and then used finite element method simulations to identify the mechanical effects of the above methods on breasts. A comparison of a breast massage administered by a midwife with the suction of breast pumps confirmed the differences in the position and direction of their tensile and compressive actions on the breasts. However, both resulted in mechanical effects inside the breast tissue, believed to be driven by changes in the position and direction of localized pressure and by the shape of the flange in a massage administered by a midwife and using breast pumps, respectively. In addition, the exerted tension or compression acts on the area just below the nipple. Thus, it can be surmised that the milk ducts, which converge directly below the nipples, are compressed in a direction perpendicular to their orientation, suggesting that this action may contribute to milk ejection.
