O16.9 Unspecified maternal hypertension, unspecified trimester

The ICD-10-CM code for Unspecified maternal hypertension, unspecified trimester is O16.9 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

15: Pregnancy, childbirth and the puerperium (O00-O9A)

Section

O10-O16: Edema, proteinuria and hypertensive disorders in pregnancy, childbirth and the puerperium (O10-O16)

Category O16

7 codes (6 billable)

FY2026 Status

Stable since FY2024

U.S. Hospital Utilization

• An estimated 255 U.S. inpatient stays in 2023 included O16.9 among the documented diagnoses.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)