O29.91 Unspecified complication of anesthesia during pregnancy, first trimester

Billable ICD-10-CM code, FY2026.

Applies from O29 Complications of anesthesia during pregnancy

Includes

• maternal complications arising from the administration of a general, regional or local anesthetic, analgesic or other sedation during pregnancy

Excludes2 (not included here)

• complications of anesthesia during labor and delivery (O74.-)
• complications of anesthesia during the puerperium (O89.-)

Use additional code

• code, if necessary, to identify the complication

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 646.81 Other specified complications of pregnancy, delivered, with or without mention of antepartum condition (approximate)
• 646.83 Other specified complications of pregnancy, 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 O29.91

Back-references to O29

• Type 2 Excludes: J12 Viral pneumonia, not elsewhere classified ("aspiration pneumonia due to anesthesia during pregnancy (O29)")
• Type 2 Excludes: J18 Pneumonia, unspecified organism ("aspiration pneumonia due to anesthesia during pregnancy (O29)")
• Type 1 Excludes: J95.4 Chemical pneumonitis due to anesthesia ("aspiration pneumonitis due to anesthesia complicating pregnancy (O29)")
• Type 1 Excludes: T41 Poisoning by, adverse effect of and underdosing of anesthetics and therapeutic gases ("complications of anesthesia during pregnancy (O29.-)")
• Type 2 Excludes: T88 Other complications of surgical and medical care, not elsewhere classified ("complications of anesthesia in pregnancy (O29.-)")
• Type 1 Excludes: T88.2 Shock due to anesthesia ("pregnancy (O29.-)")

Nearby codes

• O29.8X2 Other complications of anesthesia during pregnancy, second trimester
• O29.8X3 Other complications of anesthesia during pregnancy, third trimester
• O29.8X9 Other complications of anesthesia during pregnancy, unspecified trimester
• O29.9 Unspecified complication of anesthesia during pregnancy
• O29.90 Unspecified complication of anesthesia during pregnancy, unspecified trimester
• O29.91 Unspecified complication of anesthesia during pregnancy, first trimester (this code)
• O29.92 Unspecified complication of anesthesia during pregnancy, second trimester
• O29.93 Unspecified complication of anesthesia during pregnancy, third trimester