A mechanistic model for infant-feeding via bottles

Abstract

Recent literature has pointed out the discrepancies in flow labelling of baby bottles available in the market. In order to facilitate the categorization of labelled flow, this study is a first attempt to model milk flow out from a baby bottle under the negative suction pressure applied by a baby. The physical model results are compared with experimental measurements obtained under a controlled set of conditions using a breast pump connected to a milk bottle. The impact of applied suction pressure (ranging from low to high values in literature), bottle and nipple dimensions (corresponding to milk bottles labelled for different baby ages), tilt angle (resting versus active feeding position), bottle liquid filling level (beginning of a feed versus end of a feed) and liquid delivered (3 levels of viscosity, corresponding to water, milk and milk with cereals) on the milk flow out from a bottle is evaluated. Based on the results obtained, the relative importance of different parameters on the milk flow is discussed. The steady-state model proposed in this study delivered results in good agreement with the experimentally measured data under all scenarios. We conclude that the nipple orifice radius and suction pressure have the largest impact on milk flow, followed by the other parameters. This study allows a better understanding of parameters to be considered when designing a baby bottle. Furthermore, it can be used to more precisely label milk flow values for different bottles according the baby's age group. Thus, helping parents and healthcare practitioners to make more informed and appropriate choice from a wide range of milk bottles and nipple designs. • A static mechanistic model, based on Bernoulli's principle, for infant-feeding via baby bottles is proposed. • An experimental set-up using a breast-pump was used to validate the model predictions, and a very good agreement was found. • An infant's suction was found as the main driver of the milk flow, followed by the nipple orifice radius. • The feeding fluid viscosity and feeding angle impacted the milk flow, but at a lower extent compared to the other parameters. • The bottle shapes studied in the current work were found to have negligible impact on the milk flow.