O70.21 Third degree perineal laceration during delivery, IIIa

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

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

Applies from O70 Perineal laceration during delivery

Includes

• episiotomy extended by laceration

Excludes1 (never code together)

• obstetric high vaginal laceration alone (O71.4)

Applies from O70.2 Third degree perineal laceration during delivery

Applicable to

• Perineal laceration, rupture or tear during delivery as in O70.1, also involving anal sphincter
• Perineal laceration, rupture or tear during delivery as in O70.1, also involving rectovaginal septum
• Perineal laceration, rupture or tear during delivery as in O70.1, also involving sphincter NOS

Excludes1 (never code together)

• anal sphincter tear during delivery without third degree perineal laceration (O70.4)
• perineal laceration involving anal or rectal mucosa (O70.3)

MS-DRG index

Defines the logic of DRG(s) 769 in MDC 14.

Approximate ICD-9-CM (GEMs)

• 664.21 Third-degree perineal laceration, delivered, with or without mention of antepartum condition (approximate)
• 664.24 Third-degree perineal laceration, postpartum condition or complication (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Maternity diagnoses (age 9 through 64): Age conflict edit. These diagnoses are clinically expected only in patients age 9 through 64.

Code annotations containing back-references to O70.21

Back-references to O70.2

• Type 1 Excludes: O70.1 Second degree perineal laceration during delivery ("perineal laceration involving anal sphincter (O70.2-)")
• Type 1 Excludes: O70.4 Anal sphincter tear complicating delivery, not associated with third degree laceration ("anal sphincter tear with third degree perineal laceration (O70.2-)")

Back-references to O70

• Type 1 Excludes: N89.8 Other specified noninflammatory disorders of vagina ("current obstetric trauma (O70.-, O71.4, O71.7-O71.8)")
• Type 1 Excludes: N90 Other noninflammatory disorders of vulva and perineum ("current obstetric trauma (O70.-, O71.7-O71.8)")
• Type 1 Excludes: O71.4 Obstetric high vaginal laceration alone ("obstetric high vaginal laceration with perineal laceration (O70.-)")
• Type 1 Excludes: S31.4 Open wound of vagina and vulva ("injury to vagina and vulva during delivery (O70.-, O71.4)")

Diagnosis Index entries for O70.21

• Delivery (childbirth) (labor) › complicated › by › laceration (perineal) › perineum, perineal › third degree › with › less than 50% of external anal sphincter (EAS) thickness torn (IIIa)
• Delivery (childbirth) (labor) › complicated › by › laceration (perineal) › perineum, perineal › third degree › IIIa

Nearby codes

• O70 Perineal laceration during delivery
• O70.0 First degree perineal laceration during delivery
• O70.1 Second degree perineal laceration during delivery
• O70.2 Third degree perineal laceration during delivery
• O70.20 Third degree perineal laceration during delivery, unspecified
• O70.21 Third degree perineal laceration during delivery, IIIa (this code)
• O70.22 Third degree perineal laceration during delivery, IIIb
• O70.23 Third degree perineal laceration during delivery, IIIc
• O70.3 Fourth degree perineal laceration during delivery
• O70.4 Anal sphincter tear complicating delivery, not associated with third degree laceration
• O70.9 Perineal laceration during delivery, unspecified