Abstract: There is provided a method of measuring liquid volume in a sealed container of a breast pump of known volume comprising liquid and gas. The method includes a measurement phase, measuring the volume of gas in the container by changing a first parameter of the gas by a known amount. The method also includes measuring a change in a second parameter of the gas; calculating the volume of gas in the container using the measured change and a predetermined operation equation; and determining the volume of liquid in the container based on the calculation.

Abstract: An in-bra wearable breast pump is provided. The breast pump includes an air pump system for generating a base level vacuum and a pumping vacuum, a breast shield for receiving a user's breast and having a first side and a second side, a first channel for drawing the base level vacuum on the first side of the breast shield, and a second channel for drawing the pumping vacuum on the second side of the breast shield.