2026 ICD-10-CM Diagnosis Code O16Unspecified maternal hypertension

ICD-10-CM Codes›O00-O9A›O10-O16›O16

ICD-10-CM O16
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O16 is a non-billable ICD-10-CM category code for unspecified maternal hypertension, so it cannot be submitted on claims. Use a more specific code from this category instead, such as O16.1, O16.2, O16.3, and O16.4.

Code Identity

ICD-10-CM Code
O16
Billable Status
No — Non-Billable Category
Code Describes
Unspecified maternal hypertension
Chapter
O10-O16
Edema, proteinuria and hypertensive disorders in pregnancy, childbirth and the puerperium

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO10-O16Edema, proteinuria and hypertensive disorders in pregnancy, childbirth and the puerperium
CategoryO16Unspecified maternal hypertension
This CodeO16Unspecified maternal hypertension

Specific Coding for Unspecified maternal hypertensionOverview

Non-specific codes like O16 require more characters. Use one of these billable codes instead:

  • Use O16.1 for Unspecified maternal hypertension, first trimester

  • Use O16.2 for Unspecified maternal hypertension, second trimester

  • Use O16.3 for Unspecified maternal hypertension, third trimester

  • Use O16.4 for Unspecified maternal hypertension, complicating childbirth

  • Use O16.5 for Unspecified maternal hypertension, complicating the puerperium

  • Use O16.9 for Unspecified maternal hypertension, unspecified trimester

Patient EducationClinical

High Blood Pressure in Pregnancy

Blood pressure is the force of your blood pushing against the walls of your arteries. Your arteries are blood vessels that carry blood from your heart to other parts of your body. High blood pressure, or hypertension, is blood pressure that is higher than normal.

The full article covers:

  • What is high blood pressure in pregnancy?
  • What are the types of high blood pressure in pregnancy?
  • Who is more likely to develop high blood pressure in pregnancy?
  • What are the symptoms of high blood pressure in pregnancy?
  • What problems can high blood pressure in pregnancy cause?
  • How is high blood pressure in pregnancy diagnosed?
  • What are the treatments for high blood pressure in pregnancy?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About O16Overview

Is O16 (Unspecified maternal hypertension) a billable code?

No. This is a category header that groups the codes for unspecified maternal hypertension, and headers cannot be submitted on claims. Claims for unspecified maternal hypertension need a more specific code from this category, such as O16.1, O16.2, and O16.3.