O35.13
Maternal care for (suspected) chromosomal abnormality in fetus, Trisomy 21
Not billable — category only FY2026 2025-10-01 → 2026-09-30
Exclusions 6 never code together
O00-O9Achapter
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
1 fetus 1
2 fetus 2
3 fetus 3
4 fetus 4
5 fetus 5
9 other fetus
Instructional notes 9
O35code
Includes
- the listed conditions in the fetus as a reason for hospitalization or other obstetric care to the mother, or for termination of pregnancy
Code also
- any associated maternal condition
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 1
Alongside this code 6 same parent — O35.1
O35.10 Mat care chromosomal abnormality in fetus, unspecified category O35.11 Mat care chromosomal abnormality in fetus, Trisomy 13 category O35.12 Mat care chromosomal abnormality in fetus, Trisomy 18 category O35.14 Mat care chromosomal abnormality in fetus, Turner Syndrome category O35.15 Mat care chromosomal abnlt in fetus, sex chromosome abnlt category O35.19 Mat care chromosomal abnlt in fetus, other chromosomal abnlt category
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.