| Sub-classification | Description |
| Z38.0 | Singleton, born in hospital |
| Z38.1 | Singleton, born outside hospital |
| Z38.2 | Singleton, unspecified as to place of birth |
| Z38.3 | Twin, born in hospital |
| Z38.4 | Twin, born outside hospital |
| Z38.5 | Twin, unspecified as to place of birth |
| Z38.6 | Other multiple, born in hospital |
| Z38.7 | Other multiple, born outside hospital |
| Z38.8 | Other multiple, unspecified as to place of birth |