A breastshield unit for use with a breastpump for expressing human breastmilk has a breastshield for receiving a mothers breast and a media separation device for transferring a vacuum into the interior of the breastshield. The breastshield has a receiving area for receiving a nipple of the mothers breast. The media separation device has a media separation membrane which, for the purpose of transferring the vacuum, is movable to and fro between two positions. The media separation membrane is located in the receiving area at least in one of the two positions. Despite the integrated media separation, the breastshield unit can be made extremely compact and minimizes the dead volume.