2027 ICD-10-CM Diagnosis Code O70.21Third degree perineal laceration during delivery, IIIa

ICD-10-CM Codes›O00-O9A›O60-O77›O70

ICD-10-CM O70.21
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

O70.21 is a billable ICD-10-CM diagnosis code for third degree perineal laceration during delivery, IIIa. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 769, 776. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 254 closely related codes. 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 OB-related trauma to perineum and vulva.

Code Identity

ICD-10-CM Code
O70.21
Billable Status
Yes — Valid for Submission
Code Describes
Third degree perineal laceration during delivery, IIIa
Short Description
Third degree perineal laceration during delivery, IIIa
Same as the full description in the CMS dataset.
Parent Code
O70.2
Third degree perineal laceration during delivery

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO60-O77Complications of labor and delivery
CategoryO70Perineal laceration during delivery
This CodeO70.21Third degree perineal laceration during delivery, IIIa

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O70.21.

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).

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to O70.21: its own notes plus those printed at O70.2, O70, and Chapter 15. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From O70 Perineal laceration during delivery applies to 9 codes
  • episiotomy extended by laceration

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Third degree perineal laceration during delivery with less than 50% of external anal sphincter (EAS) thickness torn

Excludes1

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

From O70.2 Third degree perineal laceration during delivery applies to 4 codes
  • anal sphincter tear during delivery without third degree perineal laceration (O70.4)
  • perineal laceration involving anal or rectal mucosa (O70.3)
From O70 Perineal laceration during delivery applies to 9 codes
  • obstetric high vaginal laceration alone (O71.4)
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.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name O70.21, its category, or a range that includes it.

Applicable To 2

These notes mention O70.21.

  • O70.3 Fourth degree perineal laceration during delivery
    Perineal laceration, rupture or tear during delivery as in O70.2, also involving anal mucosa names O70.2, which includes this code
  • O70.3 Fourth degree perineal laceration during delivery
    Perineal laceration, rupture or tear during delivery as in O70.2, also involving rectal mucosa names O70.2, which includes this code

Excludes1 6

These codes carry an Excludes1 note naming O70.21: they are not reported together with it, unless the two conditions are unrelated.

  • N89.8 Other specified noninflammatory disorders of vagina
    current obstetric trauma (O70.-, O71.4, O71.7-O71.8) names O70.-, which includes this code
  • N90 Other noninflammatory disorders of vulva and perineum
    current obstetric trauma (O70.-, O71.7-O71.8) names O70.-, which includes this code
  • O70.1 Second degree perineal laceration during delivery
    perineal laceration involving anal sphincter (O70.2-) names O70.2-, which includes this code
  • O70.4 Anal sphincter tear complicating delivery, not associated with third degree laceration
    anal sphincter tear with third degree perineal laceration (O70.2-) names O70.2-, which includes this code
  • O71.4 Obstetric high vaginal laceration alone
    obstetric high vaginal laceration with perineal laceration (O70.-) names O70.-, which includes this code
  • S31.4 Open wound of vagina and vulva
    injury to vagina and vulva during delivery (O70.-, O71.4) names O70.-, which includes this code

Excludes2 1

These codes carry an Excludes2 note naming O70.21: its condition is not part of those codes, and both may be reported when the patient has both.

  • Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes
    obstetric trauma (O70-O71) names O70-O71, which includes this code

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 PRG026
OB-related trauma to perineum and vulva
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 O70.21 to ICD-9-CMHistory

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

ICD-9-CM
664.21 Del w 3 deg lacerat-del
Approximate The match is approximate rather than exact.
ICD-9-CM
664.24 Del w 3 deg lac-postpart
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replacement O70.21 replaces the following previously assigned code(s):

  • O70.2 - Third degree perineal laceration during delivery
FY 2019AddedAdded to the ICD-10-CM code setEffective October 1, 2018.
FY 2020–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About O70.21Overview

What is the ICD-10 code for third degree perineal laceration during delivery, IIIa?

The ICD-10-CM code for third degree perineal laceration during delivery, IIIa is O70.21 (sometimes written as O7021). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is O70.21 (Third degree perineal laceration during delivery) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report third degree perineal laceration during delivery, IIIa on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does O70.21 group to?

When third degree perineal laceration during delivery, IIIa is the principal diagnosis on an inpatient stay, it groups to MS-DRG 769, 776, with relative weights from 0.6718 to 1.6666 depending on complications. Higher weights mean higher Medicare reimbursement.

Is O70.21 a CC or MCC?

CMS lists O70.21 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 254 closely related codes in its exclusion list.

Who can O70.21 be reported for?

The Medicare Code Editor checks third degree perineal laceration during delivery, IIIa against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.