Breast shells are hollow plastic disks worn inside the brassiere to protect the nipple from becoming flattened. The disk has a hole in the middle worn toward the nipple side. It is slightly concave to conform to the shape of the breast, but can sometimes still be slightly visible under tight clothing. Shells come apart for washing. This should be done frequently, as the shell also tends to make the mother's breast sweat, which can increase bacteria growth and cause irritation.
Breast shells may be used to protect engorged or sore nipples during breastfeeding. The shell can also encourage an inverted nipple to protract (come out). If the shell is used to help ready the mother for breastfeeding, this is best done during pregnancy, as the shell can increase leaking of breast milk or colostrum. Some research suggests that breast shells used on inverted nipples may actually hinder the mother's ability to breastfeed successfully.[1]
It is also used to collect milk when the baby has not finished the teat.
Nipple shields may be confused with breast shells, but shields are intended for use during the act of breastfeeding, whereas breast shells are worn in preparation for or after breastfeeding.