| ICD-10 Code | Description |
| O30.001 | Twin pregnancy, unspecified number of placenta and unspecified number of amniotic sacs, first trimester |
| O30.002 | Twin pregnancy, unspecified number of placenta and unspecified number of amniotic sacs, second trimester |
| O30.003 | Twin pregnancy, unspecified number of placenta and unspecified number of amniotic sacs, third trimester |
| O30.009 | Twin pregnancy, unspecified number of placenta and unspecified number of amniotic sacs, unspecified trimester |
| O30.011 | Twin pregnancy, monochorionic/monoamniotic, first trimester |
| O30.012 | Twin pregnancy, monochorionic/monoamniotic, second trimester |
| O30.013 | Twin pregnancy, monochorionic/monoamniotic, third trimester |
| O30.019 | Twin pregnancy, monochorionic/monoamniotic, unspecified trimester |
| O30.021 | Conjoined twin pregnancy, first trimester |
| O30.022 | Conjoined twin pregnancy, second trimester |
| O30.023 | Conjoined twin pregnancy, third trimester |
| O30.029 | Conjoined twin pregnancy, unspecified trimester |
| O30.031 | Twin pregnancy, monochorionic/diamniotic, first trimester |
| O30.032 | Twin pregnancy, monochorionic/diamniotic, second trimester |
| O30.033 | Twin pregnancy, monochorionic/diamniotic, third trimester |
| O30.039 | Twin pregnancy, monochorionic/diamniotic, unspecified trimester |
| O30.041 | Twin pregnancy, dichorionic/diamniotic, first trimester |
| O30.042 | Twin pregnancy, dichorionic/diamniotic, second trimester |
| O30.043 | Twin pregnancy, dichorionic/diamniotic, third trimester |
| O30.049 | Twin pregnancy, dichorionic/diamniotic, unspecified trimester |
| O30.091 | Twin pregnancy, unable to determine number of placenta and number of amniotic sacs, first trimester |
| O30.092 | Twin pregnancy, unable to determine number of placenta and number of amniotic sacs, second trimester |
| O30.093 | Twin pregnancy, unable to determine number of placenta and number of amniotic sacs, third trimester |
| O30.099 | Twin pregnancy, unable to determine number of placenta and number of amniotic sacs, unspecified trimester |
