ICD-10-CM 2027 diagnosis code
O66.4Failed trial of labor
O66.4 is a header code, so it can't be reported by itself. Choose one of the 2 more specific codes beneath it.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About O66.4
O66.4 is the ICD-10-CM diagnosis code for failed trial of labor. It belongs to category O66 (other obstructed labor), block O60-O77 (complications of labor and delivery) and chapter 15 (pregnancy, childbirth and the puerperium). It is a header code, so it can't be reported by itself; one of its 2 subcodes must be used instead.
Within O66 (other obstructed labor), O66.4 is specifically for failed trial of labor. Related codes cover obstructed labor due to shoulder dystocia (O66.0), obstructed labor due to locked twins (O66.1), obstructed labor due to unusually large fetus (O66.2), obstructed labor due to other abnormalities of fetus (O66.3), attempted application of vacuum extractor and forceps (O66.5), obstructed labor due to other multiple fetuses (O66.6), other specified obstructed labor (O66.8) and obstructed labor, unspecified (O66.9).
To report this condition, pick the subcode that matches the documentation: O66.40 (unspecified) and O66.41 (delivery).
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Specific codes under O66.4
Notes that apply from higher levels
Instructions written at a parent level also apply to O66.4.
Broader instructions also apply from Chapter 15: Pregnancy, childbirth and the puerperium.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about O66.4
Is O66.4 billable?
- No. O66.4 is a header code. Report one of its more specific subcodes instead.