How can you tell if your breast pump teats and your nipple sIze match each other or You need to get a smaller/ bigger size?

An incorrectly fitted breast pump teat can cause pain and trauma to the nipple and areola, affect milk supply if breasts are not being emptied, lower the amount of milk expressed, thus leading to problems such as blocked milk ducts and mastitis. You can tell if your nipple is too big or too small for the pump if you are experiencing discomfort, pain or inadequate milk expression when pumping. The easiest way to determine if your current pump teat is the right size, or if a smaller or larger size is required, is when you are actually pumping. Make sure your nipple is positioned in the centre of the teat funnel before starting to pump. Your nipple should be moving freely in the funnel and not rub against the sides and you shouldn't feel pain. Perhaps this graphic table from (http://www.nursingangel.com.au/page/resources/choosing-the-correct-breastshield-size/) can help: