O16 ICD-10-CM Code: Unspecified maternal hypertension
O16 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC Buddy coding tools
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FY 2026 Apr update / Pregnancy, childbirth and the puerperium (O00-O9A) / Edema, proteinuria and hypertensive disorders in pregnancy, childbirth and the puerperium (O10-O16)
O16
Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidanceUnspecified maternal hypertension
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for O16. Check the code and parent instructions in the Code Book.
Excludes 2
Official- mental and behavioral disorders associated with the puerperium (F53.-)Inherited from O00-O9A
- obstetrical tetanus (A34)Inherited from O00-O9A
- postpartum necrosis of pituitary gland (E23.0)Inherited from O00-O9A
- puerperal osteomalacia (M83.0)Inherited from O00-O9A
Related Codes
Includes
OfficialNo Includes notes are included in this display for O16. Check the code and parent instructions in the Code Book.
Excludes 1
Official- supervision of normal pregnancy (Z34.-)Inherited from O00-O9A
Code First
OfficialNo Code First sequencing instructions are included in this display for O16. Check the code and parent instructions in the Code Book.
Use Additional
Official- code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.Inherited from O00-O9A
Code Also
OfficialNo Code Also instructions are included in this display for O16. Check the code and parent instructions in the Code Book.
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
- Code
- O16
- Description
- Unspecified maternal hypertension
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- No
- Payment year
- 2026
Coder workflow notes
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What This Code Means
O16 is the ICD-10-CM diagnosis code for unspecified maternal hypertension. O16 sits in the ICD-10-CM chapter for pregnancy, childbirth and the puerperium (o00-o9a), within the section covering edema, proteinuria and hypertensive disorders in pregnancy, childbirth and the puerperium (o10-o16).
Header codes like O16 cannot be reported on claims directly; they organize child codes that share clinical context. Coders should select the billable child code that matches the documented presentation and then verify its current source-backed HCC mapping. Do not infer a child code or risk adjustment value from the header alone.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for O16 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.