Medela Calma With Breast Milk Bottleis designed exclusively as an alternative to breastfeeding for mums wishing to feed their babies with breast milk. It was developed in cooperation with breastfeeding experts from the Hartmann Human Lactation Research Group at the University of Western Australia. Calma allows your baby to suck, swallow and breathe just as they learned on the breast:your baby can drink, pause and breathe in a natural rhythm, remaining calm and settled, just like on the breast.your baby needs to create a vacuum to start the milk flow, just like they do while breastfeeding.your baby can maintain their natural sucking behavior, allowing an easy transition from breast to Calma and back to breast again.