O99.411 Diseases of the circulatory system complicating pregnancy, first trimester

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

Applies from O99 Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium

Includes

• conditions which complicate the pregnant state, are aggravated by the pregnancy or are a main reason for obstetric care

Excludes2 (not included here)

• when the reason for maternal care is that the condition is known or suspected to have affected the fetus (O35-O36)

Use additional code

• code to identify specific condition

Applies from O99.4 Diseases of the circulatory system complicating pregnancy, childbirth and the puerperium

Applicable to

• Conditions in I00-I99

Excludes1 (never code together)

• peripartum cardiomyopathy (O90.3)

Excludes2 (not included here)

• hypertensive disorders (O10-O16)
• obstetric embolism (O88.-)
• venous complications and cerebrovenous sinus thrombosis in labor, childbirth and the puerperium (O87.-)
• venous complications and cerebrovenous sinus thrombosis in pregnancy (O22.-)

MS-DRG index

Defines the logic of DRG(s) 817-819 in MDC 14.

Approximate ICD-9-CM (GEMs)

• 674.01 Cerebrovascular disorders in the puerperium, delivered, with or without mention of antepartum condition (approximate)
• 674.03 Cerebrovascular disorders in the puerperium, antepartum 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 O99.411

Back-references to O99.4

• Code First: I42 Cardiomyopathy ("pre-existing cardiomyopathy complicating pregnancy and puerperium (O99.4)")
• Type 1 Excludes: O90.3 Peripartum cardiomyopathy ("pre-existing heart disease complicating pregnancy and the puerperium (O99.4-)")

Nearby codes

• O99.353 Diseases of the nervous system complicating pregnancy, third trimester
• O99.354 Diseases of the nervous system complicating childbirth
• O99.355 Diseases of the nervous system complicating the puerperium
• O99.4 Diseases of the circulatory system complicating pregnancy, childbirth and the puerperium
• O99.41 Diseases of the circulatory system complicating pregnancy
• O99.411 Diseases of the circulatory system complicating pregnancy, first trimester (this code)
• O99.412 Diseases of the circulatory system complicating pregnancy, second trimester
• O99.413 Diseases of the circulatory system complicating pregnancy, third trimester
• O99.419 Diseases of the circulatory system complicating pregnancy, unspecified trimester
• O99.42 Diseases of the circulatory system complicating childbirth
• O99.43 Diseases of the circulatory system complicating the puerperium