| O91 | Infections of breast associated with pregnancy, the puerperium and lactation | NON-BILLABLE CODE |
| O91.0 | Infection of nipple associated with pregnancy, the puerperium and lactation | NON-BILLABLE CODE |
| O91.01 | Infection of nipple associated with pregnancy | NON-BILLABLE CODE |
| O91.011 | Infection of nipple associated with pregnancy, first trimester | BILLABLE CODE |
| O91.012 | Infection of nipple associated with pregnancy, second trimester | BILLABLE CODE |
| O91.013 | Infection of nipple associated with pregnancy, third trimester | BILLABLE CODE |
| O91.019 | Infection of nipple associated with pregnancy, unspecified trimester | BILLABLE CODE |
| O91.02 | Infection of nipple associated with the puerperium | BILLABLE CODE |
| O91.03 | Infection of nipple associated with lactation | BILLABLE CODE |
| O91.1 | Abscess of breast associated with pregnancy, the puerperium and lactation | NON-BILLABLE CODE |
| O91.11 | Abscess of breast associated with pregnancy | NON-BILLABLE CODE |
| O91.111 | Abscess of breast associated with pregnancy, first trimester | BILLABLE CODE |
| O91.112 | Abscess of breast associated with pregnancy, second trimester | BILLABLE CODE |
| O91.113 | Abscess of breast associated with pregnancy, third trimester | BILLABLE CODE |
| O91.119 | Abscess of breast associated with pregnancy, unspecified trimester | BILLABLE CODE |
| O91.12 | Abscess of breast associated with the puerperium | BILLABLE CODE |
| O91.13 | Abscess of breast associated with lactation | BILLABLE CODE |
| O91.2 | Nonpurulent mastitis associated with pregnancy, the puerperium and lactation | NON-BILLABLE CODE |
| O91.21 | Nonpurulent mastitis associated with pregnancy | NON-BILLABLE CODE |
| O91.211 | Nonpurulent mastitis associated with pregnancy, first trimester | BILLABLE CODE |
| O91.212 | Nonpurulent mastitis associated with pregnancy, second trimester | BILLABLE CODE |
| O91.213 | Nonpurulent mastitis associated with pregnancy, third trimester | BILLABLE CODE |
| O91.22 | Nonpurulent mastitis associated with the puerperium | BILLABLE CODE |
| O91.23 | Nonpurulent mastitis associated with lactation | BILLABLE CODE |
