O41.121 — Chorioamnionitis, first trimester
Is O41.121 billable?
No — O41.121 is a non-billable header code. O41.121 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 7 billable codes beneath O41.121.
Billable codes under this header
- O41.1210Chorioamnionitis, first trimester, not applicable or unspecified
- O41.1211Chorioamnionitis, first trimester, fetus 1
- O41.1212Chorioamnionitis, first trimester, fetus 2
- O41.1213Chorioamnionitis, first trimester, fetus 3
- O41.1214Chorioamnionitis, first trimester, fetus 4
- O41.1215Chorioamnionitis, first trimester, fetus 5
- O41.1219Chorioamnionitis, first trimester, other fetus
O41.121 at a glance
| Code | O41.121 |
|---|---|
| Description | Chorioamnionitis, first trimester |
| Billable | No — header code |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
How is O41.121 listed in the Alphabetic Index?
The Alphabetic Index lists these routes under O41.12, the nearest indexed parent of O41.121. Use them to find the family, then select the specific code.
- Chorioamnionitis
- Triple I
- Infection, infected, infective › intrauterine inflammation (opportunistic)
- Infection, infected, infective › amniotic fluid, sac or cavity › chorioamnionitis (opportunistic)
- Pregnancy › complicated by › amnionitis (single) (uterine)
- Pregnancy › complicated by › chorioamnionitis (single) (uterine)
- Pregnancy › complicated by › infection › intrauterine (single) (uterine)
- Pregnancy › complicated by › inflammation › intrauterine (single) (uterine)
Excludes1 — never code together — inherited from Chapter 15
The conditions below can never be reported together with O41.121 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- supervision of normal pregnancy (Z34.-)
Excludes1 — never code together — inherited from O41
The conditions below can never be reported together with O41.121 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- encounter for suspected maternal and fetal conditions ruled out (Z03.7-)
Use additional code — inherited from Chapter 15
Report an additional code alongside O41.121 to fully describe the condition. O41.121 is sequenced first.
- code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.
Excludes2 — not included here — inherited from Chapter 15
The conditions below are not part of O41.121, but a patient may have both at the same time. When documentation supports it, O41.121 and the excluded code may both be reported.
What codes fall under O41.121? (7)
- O41.1210Chorioamnionitis, first trimester, not applicable or unspecified
- O41.1211Chorioamnionitis, first trimester, fetus 1
- O41.1212Chorioamnionitis, first trimester, fetus 2
- O41.1213Chorioamnionitis, first trimester, fetus 3
- O41.1214Chorioamnionitis, first trimester, fetus 4
- O41.1215Chorioamnionitis, first trimester, fetus 5
- O41.1219Chorioamnionitis, first trimester, other fetus
How long has O41.121 existed?
O41.121 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.