O16 — Unspecified maternal hypertension
Is O16 billable?
No — O16 is a non-billable header code. O16 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 6 billable codes beneath O16.
Billable codes under this header
- O16.1Unspecified maternal hypertension, first trimester
- O16.2Unspecified maternal hypertension, second trimester
- O16.3Unspecified maternal hypertension, third trimester
- O16.4Unspecified maternal hypertension, complicating childbirth
- O16.5Unspecified maternal hypertension, complicating the puerperium
- O16.9Unspecified maternal hypertension, unspecified trimester
O16 at a glance
| Code | O16 |
|---|---|
| Description | Unspecified maternal hypertension |
| Billable | No — header code |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Excludes1 — never code together — inherited from Chapter 15
The conditions below can never be reported together with O16 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.-)
Use additional code — inherited from Chapter 15
Report an additional code alongside O16 to fully describe the condition. O16 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 O16, but a patient may have both at the same time. When documentation supports it, O16 and the excluded code may both be reported.
What codes fall under O16? (6)
- O16.1Unspecified maternal hypertension, first trimester
- O16.2Unspecified maternal hypertension, second trimester
- O16.3Unspecified maternal hypertension, third trimester
- O16.4Unspecified maternal hypertension, complicating childbirth
- O16.5Unspecified maternal hypertension, complicating the puerperium
- O16.9Unspecified maternal hypertension, unspecified trimester
How long has O16 existed?
O16 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.
Which codes are confused with O16?
ICD-10-CM declares these codes mutually exclusive with O16 — exactly one of each pair can be correct for a given encounter.