O99.1 ICD-10-CA subcategory: Other diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism complicating pregnancy, childbirth and the puerperium

O99.1 isn’t a code on its own. Choose one of the 5 codes beneath it, the one the documentation supports.

Official description

O99.1

Other diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism complicating pregnancy, childbirth and the puerperium

ICD-10-CA · Canada · Also written O991

Codes in O99.1

O99.1 isn’t a code on its own. Open the code that matches what the note documents.

O99.101Other diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism complicating pregnancy, childbirth and the puerperium, delivered, with…O99.102Other diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism complicating pregnancy, childbirth and the puerperium, delivered, with…O99.103Other diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism complicating pregnancy, childbirth and the puerperium, antepartum…O99.104Other diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism complicating pregnancy, childbirth and the puerperium, postpartum…O99.109Other diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism complicating pregnancy, childbirth and the puerperium, unspecified as to…

Notes for O99.1

As CIHI prints them, with any note O99.1 takes from the headings above it.

Includes

• Conditions in D65-D89

Use additional code

Add a code for this detail when the note documents it.

Use additional code to identify specific condition.From O99 Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium

Excludes

Conditions classified elsewhere.

• haemorrhage with coagulation defects(O46.00, O67.0-,O72.3-)
Infectious and parasitic diseases (O98.-)injury, poisoning and certain other consequences of external causes (S00-T98)when the reason for maternal care is that the condition is known or suspected to have affected the fetus (O35-O36)From O99 Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium
Certain diseases or injuries complicating pregnancy, childbirth, and the puerperium classified elsewhere:external causes (for mortality) (V,W,X,Y)injury, poisoning and certain other consequences of external causes (S00-T88.1, T88.6-T98)mental and behavioural disorders associated with the puerperium (F53.-)obstetrical tetanus (A34)postpartum necrosis of pituitary gland (E23.0)puerperal osteomalacia (M83.0)supervision of:• high-risk pregnancy (Z35.-)• normal pregnancy (Z34.-)From Chapter 15: Pregnancy, childbirth and the puerperium (O00-O99)

Note

This category includes conditions which complicate the pregnant state, are aggravated by the pregnancy or are a main reason for obstetric care and for which the Alphabetical Index does not indicate a specific rubric in Chapter XV.From O99 Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium
For use of categories O95-O97 reference should be made to the mortality coding rules and guidelines.From O94-O99 Other obstetric conditions, not elsewhere classified
The codes included in this chapter are to be used for conditions related to or aggravated by the pregnancy, childbirth or by the puerperium (maternal causes or obstetric causes)From Chapter 15: Pregnancy, childbirth and the puerperium (O00-O99)

Where O99.1 sits

1ChapterChapter 15: Pregnancy, childbirth and the puerperium (O00-O99)
2Block O94-O99Other obstetric conditions, not elsewhere classified
3Category O99Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium
4Subcategory O99.1Other diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism complicating pregnancy, childbirth and the puerperium

Source and release

Data release: ICD-10-CA · FY 2026–2027
Effective date: Apr 1, 2026
Publisher: CIHI

This page is built from the ICD-10-CA catalog that Vero Codes reads when it suggests codes: Canadian Institute for Health Information’s FY 2026–2027 release, imported from the publisher’s file and checked against it. The description, notes and structured data come from the same record.

See O99.1 in the CIHI source

Frequently asked questions

Is O99.1 a valid ICD-10-CA code?

No. O99.1 (Other diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism complicating pregnancy, childbirth and the puerperium) is a subcategory heading in CIHI’s ICD-10-CA FY 2026–2027 release. It holds 5 codes; record the one the documentation supports.

Where is O99.1 in ICD-10-CA?

O99.1 sits under O99 Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium, within O94-O99 Other obstetric conditions, not elsewhere classified, within Chapter 15: Pregnancy, childbirth and the puerperium (O00-O99).

What coding notes apply to O99.1?

ICD-10-CA lists Includes, Excludes, Note, Use additional code notes for O99.1, including those from the headings it sits under. They are listed on this page with where each one comes from.

Which ICD-10-CA release does this page use?

It uses CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026 to Mar 31, 2027. It is a reference: confirm the code against the current list and the payer’s rules before you submit it.

View O99