2027 ICD-10-CM Diagnosis Code O42.00Premature rupture of membranes, onset of labor within 24 hours of rupture, unspecified weeks of gestation

ICD-10-CM Codes›O00-O9A›O30-O48›O42

ICD-10-CM O42.00
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

O42.00 is a billable ICD-10-CM diagnosis code for premature rupture of membranes, onset of labor within 24 hours of rupture, unspecified weeks of gestation. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) 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 prem rupture of membranes onset of labor within 24 hours. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Early or threatened labor.

Code Identity

ICD-10-CM Code
O42.00
Billable Status
Yes — Valid for Submission
Code Describes
Premature rupture of membranes, onset of labor within 24 hours of rupture, unspecified weeks of gestation
Short Description
Prem ROM, onset labor w/n 24 hr of rupt, unsp weeks of gest
Parent Code
O42.0
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 CodeO42.00Premature rupture of membranes, onset of labor within 24 hours of rupture, unspecified weeks of gestation

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O42.00.

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.

  • Prem rupture of membranes onset of labor within 24 hours

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to O42.00: its own notes plus those printed at Chapter 15. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • supervision of normal pregnancy (Z34.-)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • mental and behavioral disorders associated with the puerperium (F53.-)
  • obstetrical tetanus (A34)
  • postpartum necrosis of pituitary gland (E23.0)
  • puerperal osteomalacia (M83.0)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.

Notes

General instructions on how these codes are used.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • CODES FROM THIS CHAPTER ARE FOR USE ONLY ON MATERNAL RECORDS, NEVER ON NEWBORN RECORDS
  • Codes from this chapter are for use for conditions related to or aggravated by the pregnancy, childbirth, or by the puerperium (maternal causes or obstetric causes)
  • Trimesters are counted from the first day of the last menstrual period. They are defined as follows:
  • 1st trimester- less than 14 weeks 0 days
  • 2nd trimester- 14 weeks 0 days to less than 28 weeks 0 days
  • 3rd trimester- 28 weeks 0 days until delivery

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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

Clinical InformationClinical

  • Premature Rupture of Membrane

    spontaneous rupture of fetal membranes that occurs before the onset of labor. if rupture occurs before 37 weeks of gestation then the correct diagnosis is preterm premature rupture of membranes.

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 O42.00 to ICD-9-CMHistory

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

ICD-9-CM
658.10 Prem rupt membran-unspec
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About O42.00Overview

Is O42.00 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report premature rupture of membranes, onset of labor within 24 hours of rupture, unspecified weeks of gestation on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does O42.00 group to?

When premature rupture of membranes, onset of labor within 24 hours of rupture, unspecified weeks of gestation is the principal diagnosis on an inpatient stay, it groups to MS-DRG 833, 832, 831, 819, 818, 817, with relative weights from 0.5000 to 1.7586 depending on complications. Higher weights mean higher Medicare reimbursement.

Who can O42.00 be reported for?

The Medicare Code Editor checks premature rupture of membranes, onset of labor within 24 hours of rupture, unspecified weeks of gestation 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 O42.00?

Under the General Equivalence Mappings, premature rupture of membranes, onset of labor within 24 hours of rupture, unspecified weeks of gestation converts to ICD-9-CM 658.10 (prem rupt membran-unspec). The mapping is approximate, so confirm the match fits the documentation.