2026 ICD-10-CM Diagnosis Code O48.1Prolonged pregnancy

ICD-10-CM Codes›O00-O9A›O30-O48›O48

ICD-10-CM O48.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O48.1 is a billable ICD-10-CM diagnosis code for prolonged pregnancy. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 817 through 819, 831 through 833. The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64). Coders also document this condition as postmaturity of fetus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Prolonged pregnancy.

Code Identity

ICD-10-CM Code
O48.1
Billable Status
Yes — Valid for Submission
Code Describes
Prolonged pregnancy
Short Description
Prolonged pregnancy
Same as the full description in the CMS dataset.
Parent Code
O48
Late pregnancy

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO30-O48Maternal care related to the fetus and amniotic cavity and possible delivery problems
CategoryO48Late pregnancy
This CodeO48.1Prolonged pregnancy

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O48.1.

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.

  • Postmaturity of fetus

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Pregnancy which has advanced beyond 42 completed weeks gestation

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.

    • Post-dates(40-42 weeks) (pregnancy) (mother)
      • more than 42 weeks gestation
    • Postmaturity, postmature(over 42 weeks)
      • maternal (over 42 weeks gestation)
    • Post-term(40-42 weeks) (pregnancy) (mother)
      • more than 42 weeks gestation (mother)
    • Pregnancy(single) (uterine)
      • complicated by (care of) (management affected by)
        • postmaturity (post-term) (40 to 42 weeks)
          • more than 42 completed weeks gestation (prolonged)
    • Pregnancy(single) (uterine)
      • postmature (40 to 42 weeks)
        • more than 42 weeks gestation
    • Pregnancy(single) (uterine)
      • prolonged (more than 42 weeks gestation)
    • Prolonged, prolongation(of)
      • gestation (over 42 completed weeks)
        • mother
    • Prolonged, prolongation(of)
      • pregnancy (more than 42 weeks gestation)

Clinical ClassificationClinical

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

CCSR PRG022
Prolonged pregnancy
Default principal diagnosis: inpatient Yes · outpatient Yes

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 O48.1 to ICD-9-CMHistory

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

ICD-9-CM
645.23 Prolonged preg-antepar
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 O48.1Overview

Is O48.1 (Late pregnancy) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report prolonged pregnancy on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does O48.1 group to?

When prolonged pregnancy is the principal diagnosis on an inpatient stay, it groups to MS-DRG 817, 818, 819, 831, 832, 833, with relative weights from 0.5229 to 1.6880 depending on complications. Higher weights mean higher Medicare reimbursement.

Who can O48.1 be reported for?

The Medicare Code Editor checks prolonged pregnancy 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 O48.1?

Under the General Equivalence Mappings, prolonged pregnancy converts to ICD-9-CM 645.23 (prolonged preg-antepar). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.