O35.13X0
Maternal care for (suspected) chromosomal abnormality in fetus, Trisomy 21, not applicable or unspecified
This code does not map to a risk-adjusting HCC in the loaded models.
Coding notes
Excludes 1 never coded together · Excludes 2 may co-exist
the listed conditions in the fetus as a reason for hospitalization or other obstetric care to the mother, or for termination of pregnancy
encounter for suspected maternal and fetal conditions ruled out (Z03.7-)
any associated maternal condition
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.
| Character | Meaning |
|---|---|
| 0 | not applicable or unspecified |
| 1 | fetus 1 |
| 2 | fetus 2 |
| 3 | fetus 3 |
| 4 | fetus 4 |
| 5 | fetus 5 |
| 9 | other fetus |
supervision of normal pregnancy (Z34.-)
mental and behavioral disorders associated with the puerperium (F53.-) obstetrical tetanus (A34) postpartum necrosis of pituitary gland (E23.0) puerperal osteomalacia (M83.0)
code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.
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
Official Guidelines for O35.13X0
FY 2026 ›Subsections
- I.C.15.aGeneral Rules for Obstetric Cases
- I.C.15.bSelection of OB Principal or First-listed Diagnosis
- I.C.15.cPre-existing conditions versus conditions due to the pregnancy
- I.C.15.dPre-existing hypertension in pregnancy
- I.C.15.eFetal Conditions Affecting the Management of the Mother
- I.C.15.fHIV Infection in Pregnancy, Childbirth and the Puerperium
- I.C.15.gDiabetes mellitus in pregnancy
- I.C.15.hLong term use of insulin and oral hypoglycemics
- I.C.15.iGestational (pregnancy induced) diabetes
- I.C.15.jSepsis and septic shock complicating abortion, pregnancy, childbirth and the puerperium
- I.C.15.kPuerperal sepsis
- I.C.15.lAlcohol, tobacco and drug use during pregnancy, childbirth and the puerperium
- I.C.15.mPoisoning, toxic effects, adverse effects and underdosing in a pregnant patient
- I.C.15.nNormal Delivery, Code O80
- I.C.15.oThe Peripartum and Postpartum Periods
- I.C.15.pCode O94, Sequelae of complication of pregnancy, childbirth, and the puerperium
- I.C.15.qTermination of Pregnancy and Spontaneous abortions
- I.C.15.rAbuse in a pregnant patient
- I.C.15.sCOVID-19 infection in pregnancy, childbirth, and the puerperium
Sections that reference O35.13X0
- I.C.15.a.5)Unspecified trimester
… for fetus identification Where applicable, a 7th character is to be assigned for certain categories (O31, O32, O33.3 - O33.6, O35, O36, O40, O41, O60.1, O60.2, O64, and O69) to identify the fetus for which the complication code applies. …
- I.C.15.e.1)Codes from categories O35 and O36
Codes from categories O35, Maternal care for known or suspected fetal abnormality and damage, and O36, Maternal care for other fetal problems, are …
- I.C.15.e.2)In utero surgery
In cases when surgery is performed on the fetus, a diagnosis code from category O35, Maternal care for known or suspected fetal abnormality and damage, should be assigned identifying the fetal condition. …
- I.C.21.c.6)ObservationChapter 21
… suspected fetal condition that are inconclusive following testing and evaluation, assign the appropriate code from category O35, O36, O40 or O41. …
- I.C.15.a.1)Codes from chapter 15 and sequencing priority
Obstetric cases require codes from chapter 15, codes in the range O00- O9A, Pregnancy, Childbirth, and the Puerperium. …
Sections whose FY 2026 text names O35.13X0, its O35 category, or a range containing it — the chapter guidance above is the authoritative source.