BREAST PUMP

The present invention relates to a breast pump (1) shaped at least in part to fit inside a bra and built to accumulate milk (M) expressed from a breast of a lactating mother in a milk container (36), the breast pump (1) comprising- a housing (2),- a suction source (4),- a breast shield element (24) with a nipple tunnel (28) adapted to receive a nipple,- a sensor means (210) including an emitter (211) for an emission of electromagnetic waves and a receiver (212) for a reception of the electromagnetic waves, designed to provide a sensor signal for a detection of the milk (M),- a controller (200) for controlling the suction source (4) and adapted to receive the sensor signal, and- milk (M),wherein the transparent section (360) has a protrusion (362) arranged to be in front of and to face away from the corresponding sensor means (210) in order to be wetted by the milk (M) and in order to reflect and/or refract the electromagnetic waves from the emitter (211).