Some noticeable details signal a poor fit of your breast pump flange:
Your nipple is compressed in the flange tunnel: the flange is too small.
Part of the areola is sucked in with the nipple: the flange is too large.
The nipple is sore and red: the flange is too small.
The areola has marks and is sore: the flange is too large.
A bad fit causes painful expression, irritation, and soreness. Be sure to find the best fit for your needs. Read more