2026 ICD-10-CM Diagnosis Code O10.42Pre-existing secondary hypertension complicating childbirth

ICD-10-CM Codes›O00-O9A›O10-O16›O10

ICD-10-CM O10.42
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O10.42 is a billable ICD-10-CM diagnosis code for pre-existing secondary hypertension complicating childbirth. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64). Coders also document this condition as hypertension secondary to renal disease complicating AND/OR reason for care during childbirth. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complications specified during childbirth, Hypertension and hypertensive-related conditions complicating pregnancy; childbirth; and the puerperium, and Hypertension with complications and secondary hypertension.

Code Identity

ICD-10-CM Code
O10.42
Billable Status
Yes — Valid for Submission
Code Describes
Pre-existing secondary hypertension complicating childbirth
Short Description
Pre-existing secondary hypertension complicating childbirth
Same as the full description in the CMS dataset.
Parent Code
O10.4
Pre-existing secondary hypertension complicating 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
CategoryO10Pre-existing hypertension complicating pregnancy, childbirth and the puerperium
This CodeO10.42Pre-existing secondary hypertension complicating childbirth

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O10.42.

Maternity diagnoses
The Medicare Code Editor detects inconsistencies in maternity cases by checking a patient's age and any diagnosis on the patient's record. The maternity code edits apply to patients age ange is 9–64 years inclusive (e.g., diabetes in pregnancy, antepartum pulmonary complication).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Hypertension secondary to renal disease complicating AND/OR reason for care during childbirth
  • Hypertension secondary to renal disease in obstetric context
  • Pre-existing secondary hypertension complicating pregnancy, childbirth and puerperium

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Hypertension, hypertensive(accelerated) (benign) (essential) (idiopathic) (malignant) (systemic)
      • complicating
        • childbirth (labor)
          • secondary

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR PRG023
Complications specified during childbirth
Default principal diagnosis: inpatient No · outpatient No
CCSR PRG020
Hypertension and hypertensive-related conditions complicating pregnancy; childbirth; and the puerperium
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR CIR008
Hypertension with complications and secondary hypertension
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Childbirth Problems

Childbirth is the process of giving birth to a baby. It includes labor and delivery. Usually everything goes well, but problems can happen. They may cause a risk to the mother, baby, or both. Some of the more common childbirth problems include:

Read the full article at MedlinePlus

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

Convert O10.42 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
642.11 Renal hyperten pg-deliv
Approximate The match is approximate rather than exact.

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 O10.42Overview

Is O10.42 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report pre-existing secondary hypertension complicating childbirth on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Who can O10.42 be reported for?

The Medicare Code Editor checks pre-existing secondary hypertension complicating childbirth against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.

What is the ICD-9 equivalent of O10.42?

Under the General Equivalence Mappings, pre-existing secondary hypertension complicating childbirth converts to ICD-9-CM 642.11 (renal hyperten pg-deliv). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.