Alphabetic Index FY2027

O99

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

FY2027Chapter 15: Pregnancy, childbirth and the puerperium/O94–O9A Other obstetric conditions, not elsewhere classified

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

O99 is a non-billable ICD-10-CM code category for other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are O99.0 Anemia complicating pregnancy, childbirth and the puerperium; O99.1 Other diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism complicating pregnancy, childbirth and the puerperium; O99.2 Endocrine, nutritional and metabolic diseases complicating pregnancy, childbirth and the puerperium; O99.3 Mental disorders and diseases of the nervous system complicating pregnancy, childbirth and the puerperium and 5 more. Its coding notes include a Use additional code instruction, 1 Excludes1 entry and 5 Excludes2 entries.

Guidelines tip

From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.

The trimester character comes from the provider's documentation for the current encounter. The unspecified trimester code should rarely be used.

Guidelines I.C.15.a.3; I.C.15.a.5Pregnancy: the trimester characterRead the official text

Use additional code

Add the listed code as a secondary code, if known.

This code
  • code to identify specific condition
Also from chapter/block level (1 note)
Inherited from Chapter 15 Pregnancy, childbirth and the puerperium
  • code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.

Excludes1

Not coded here. The listed conditions generally should not be reported together.

Also from chapter/block level (1 note)
Inherited from Chapter 15 Pregnancy, childbirth and the puerperium
  • supervision of normal pregnancy (Z34.-)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

This code
  • when the reason for maternal care is that the condition is known or suspected to have affected the fetus (O35-O36)
Also from chapter/block level (4 notes)
Inherited from Chapter 15 Pregnancy, childbirth and the puerperium
  • mental and behavioral disorders associated with the puerperium (F53.-)
  • obstetrical tetanus (A34)
  • postpartum necrosis of pituitary gland (E23.0)
  • puerperal osteomalacia (M83.0)

Includes

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

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

Notes

Also from chapter/block level (6 notes)
Inherited from Chapter 15 Pregnancy, childbirth and the puerperium
  • 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

More specific codes under O99 9