| O66 | Other obstructed labor | NON-BILLABLE CODE |
| O66.1 | Obstructed labor due to locked twins | BILLABLE CODE |
| O66.2 | Obstructed labor due to unusually large fetus | BILLABLE CODE |
| O66.3 | Obstructed labor due to other abnormalities of fetus | BILLABLE CODE |
| O66.4 | Failed trial of labor | NON-BILLABLE CODE |
| O66.40 | Failed trial of labor, unspecified | BILLABLE CODE |
| O66.41 | Failed attempted vaginal birth after previous cesarean delivery | BILLABLE CODE |
| O66.5 | Attempted application of vacuum extractor and forceps | BILLABLE CODE |
| O66.6 | Obstructed labor due to other multiple fetuses | BILLABLE CODE |
| O66.8 | Other specified obstructed labor | BILLABLE CODE |
| O66.9 | Obstructed labor, unspecified | BILLABLE CODE |
