O36.1920

Maternal care for other isoimmunization, second trimester, not applicable or unspecified

Billable FY2026 2025-10-01 → 2026-09-30

This is the unspecified option. 6 more specific codes sit alongside it. Worth checking whether the documentation supports one of them.

Exclusions 8 never code together

O36code

Excludes1

encounter for suspected maternal and fetal conditions ruled out (Z03.7-)Z03.7-
placental transfusion syndromes (O43.0-)O43.0-

Excludes2

labor and delivery complicated by fetal stress (O77.-)O77.-

O00-O9Achapter

Excludes1

supervision of normal pregnancy (Z34.-)Z34.-

Excludes2

mental and behavioral disorders associated with the puerperium (F53.-)F53.-
obstetrical tetanus (A34)A34
postpartum necrosis of pituitary gland (E23.0)E23.0
puerperal osteomalacia (M83.0)M83.0

Excludes1 — never code together. The excluded condition and this one are mutually exclusive.

Excludes2 — not included here, but the patient may have both. Code both when documented.

7th character 7

0 not applicable or unspecified this code

1 fetus 1

2 fetus 2

3 fetus 3

4 fetus 4

5 fetus 5

9 other fetus

Instructional notes 9

O36code

Includes

the listed conditions in the fetus as a reason for hospitalization or other obstetric care of the mother, or for termination of pregnancy

O36.1code

Inclusion terms

Maternal care for ABO isoimmunization

O00-O9Achapter

Notes

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

Use additional code

code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.Z3A

Index entries leading here 3

Incompatibility
- ABO
  - affecting management of pregnancy O36.11
    - anti-B sensitization O36.19
    - specified NEC O36.19
- blood (group) (Duffy) (K) (Kell) (Kidd) (Lewis) (M) (S) NEC
  - affecting management of pregnancy O36.11
    - anti-B sensitization O36.19
Isoimmunization NEC — see also Incompatibility
- affecting management of pregnancy (ABO) (with hydrops fetalis) O36.11
  - anti-B sensitization O36.19
  - specified NEC O36.19
Pregnancy (single) (uterine) Z33.1
- complicated by (care of) (management affected by)
  - isoimmunization O36.11
    - anti-B sensitization O36.19
    - specified NEC O36.19

Alongside this code 6 same parent — O36.192

O36.1921 Maternal care for oth isoimmun, second trimester, fetus 1 O36.1922 Maternal care for oth isoimmun, second trimester, fetus 2 O36.1923 Maternal care for oth isoimmun, second trimester, fetus 3 O36.1924 Maternal care for oth isoimmun, second trimester, fetus 4 O36.1925 Maternal care for oth isoimmun, second trimester, fetus 5 O36.1929 Maternal care for oth isoimmunization, second trimester, oth

Medications 1

5 Pregnancy Trimester, Second drugs

MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.

Additional references

AHA Coding Clinic® Licence required

Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.

Risk adjustment

Maps to no condition category in any loaded model.

Presence is a property of the code. Untick a model to hide it everywhere.

This code

Billable: yes
Code set: FY2026
Parent: O36.192
Block: O30-O48
Siblings: 6

Present FY2024–FY2027.