Alphabetic Index FY2027

O35

Maternal care for known or suspected fetal abnormality and damage

FY2027Chapter 15: Pregnancy, childbirth and the puerperium/O30–O48 Maternal care related to the fetus and amniotic cavity and possible delivery problems

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

O35 is a non-billable ICD-10-CM code category for maternal care for known or suspected fetal abnormality and damage. 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 O35.0 Maternal care for (suspected) central nervous system malformation in fetus; O35.1 Maternal care for (suspected) chromosomal abnormality in fetus; O35.A Maternal care for other (suspected) fetal abnormality and damage, fetal facial anomalies; O35.B Maternal care for other (suspected) fetal abnormality and damage, fetal cardiac anomalies and 14 more. Its coding notes include a Use additional code instruction, a Code also instruction, 2 Excludes1 entries and 4 Excludes2 entries.

7th characters

Every code below needs one of these.

One of the following 7th characters is to be assigned to each code under category O35. 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 O35 that has a 7th character of 1 through 9.

  • 0not applicable or unspecified
  • 1fetus 1
  • 2fetus 2
  • 3fetus 3
  • 4fetus 4
  • 5fetus 5
  • 9other fetus

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.

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.

Code also

Two codes may be needed to describe the condition. This note gives no sequencing order.

This code
  • any associated maternal condition

Excludes1

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

This code
  • encounter for suspected maternal and fetal conditions ruled out (Z03.7-)
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.

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

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 O35 18