2026 ICD-10-CM Diagnosis Code O42.012Preterm premature rupture of membranes, onset of labor within 24 hours of rupture, second trimester

ICD-10-CM Codes›O00-O9A›O30-O48›O42

ICD-10-CM O42.012
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O42.012 is a billable ICD-10-CM diagnosis code for preterm premature rupture of membranes, onset of labor within 24 hours of rupture, second trimester. 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). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Early or threatened labor.

Code Identity

ICD-10-CM Code
O42.012
Billable Status
Yes — Valid for Submission
Code Describes
Preterm premature rupture of membranes, onset of labor within 24 hours of rupture, second trimester
Short Description
Pretrm prem ROM, onset labor w/n 24 hours of rupt, 2nd tri
Parent Code
O42.01
Preterm premature rupture of membranes, onset of labor within 24 hours of rupture

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO30-O48Maternal care related to the fetus and amniotic cavity and possible delivery problems
CategoryO42Premature rupture of membranes
This CodeO42.012Preterm premature rupture of membranes, onset of labor within 24 hours of rupture, second trimester

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O42.012.

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).

Clinical ClassificationClinical

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

CCSR PRG011
Early or threatened labor
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 O42.012 to ICD-9-CMHistory

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

ICD-9-CM
658.11 Prem rupt membran-deliv
Approximate The match is approximate rather than exact.
ICD-9-CM
658.13 Prem rupt memb-antepart
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 O42.012Overview

Is O42.012 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report preterm premature rupture of membranes, onset of labor within 24 hours of rupture, second trimester on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does O42.012 group to?

When preterm premature rupture of membranes, onset of labor within 24 hours of rupture, second trimester 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 O42.012 be reported for?

The Medicare Code Editor checks preterm premature rupture of membranes, onset of labor within 24 hours of rupture, second trimester 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 O42.012?

Under the General Equivalence Mappings, preterm premature rupture of membranes, onset of labor within 24 hours of rupture, second trimester converts to ICD-9-CM 658.11 (prem rupt membran-deliv) and 658.13 (prem rupt memb-antepart). 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.