Coding and coverage · ICD-10-CM

O36 › O36.1 › O36.19

O36.192 Maternal care for other isoimmunization, second trimester

Not billable (header)Chapter 15

This code needs a 7th character (use X as a placeholder for missing characters).

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7th character codes

  • O36.1920 Maternal care for other isoimmunization, second trimester, not applicable or unspecified
  • O36.1921 Maternal care for other isoimmunization, second trimester, fetus 1
  • O36.1922 Maternal care for other isoimmunization, second trimester, fetus 2
  • O36.1923 Maternal care for other isoimmunization, second trimester, fetus 3
  • O36.1924 Maternal care for other isoimmunization, second trimester, fetus 4
  • O36.1925 Maternal care for other isoimmunization, second trimester, fetus 5
  • O36.1929 Maternal care for other isoimmunization, second trimester, other fetus

Instructional notes

Chapter 15

Excludes1Not coded here: never report with this code, except when the two conditions are unrelated.
  • supervision of normal pregnancy (Z34.-)
Excludes2Not included here: the patient may have both; report both when both are present.
  • mental and behavioral disorders associated with the puerperium (F53.-)
  • obstetrical tetanus (A34)
  • postpartum necrosis of pituitary gland (E23.0)
  • puerperal osteomalacia (M83.0)
Use additional codeAdd a second code for the full picture.
  • code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.
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

O36

Excludes1Not coded here: never report with this code, except when the two conditions are unrelated.
  • encounter for suspected maternal and fetal conditions ruled out (Z03.7-)
  • placental transfusion syndromes (O43.0-)
Excludes2Not included here: the patient may have both; report both when both are present.
  • labor and delivery complicated by fetal stress (O77.-)
Includes
  • the listed conditions in the fetus as a reason for hospitalization or other obstetric care of the mother, or for termination of pregnancy
7th charactersOne of the following 7th characters is to be assigned to each code under category O36. 7th character 0 is for single gestations and multiple gestations where the fetus is unspecified. 7th characters 1 through 9 are for cases of multiple gestations to identify the fetus for which the code applies. The appropriate code from category O30, Multiple gestation, must also be assigned when assigning a code from category O36 that has a 7th character of 1 through 9.
  • 0 not applicable or unspecified
  • 1 fetus 1
  • 2 fetus 2
  • 3 fetus 3
  • 4 fetus 4
  • 5 fetus 5
  • 9 other fetus

O36.1

Inclusion terms
  • Maternal care for ABO isoimmunization

O36.19

Inclusion terms
  • Maternal care for Anti-B sensitization

Chapter 15: Pregnancy, childbirth and the puerperium (O00-O9A) · O30-O48 Maternal care related to the fetus and amniotic cavity and possible delivery problems (O30-O48)

Source: ICD-10-CM FY 2027 code descriptions and tabular list (CMS and CDC National Center for Health Statistics), effective 2026-10-01 through 2027-09-30 · CMS ICD-10 files. HCC mapping: CMS-HCC V28, payment year 2027. As of 2026-11-04.

Coverage and payment depend on the claim details; confirm with the Medicare Administrative Contractor.