Is O35.0 a billable ICD-10-CM code?

No. O35.0 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does O35.0 sit in the tabular list?

Pregnancy, childbirth and the puerperium (O00-O9A), in the block Maternal care related to the fetus and amniotic cavity and possible delivery problems (O30-O48).

What cannot be coded together with O35.0?

O35.0 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above O35.0 (O35) and apply to it just the same.

O35.0

O35.0 — Maternal care for (suspected) central nervous system malformation in fetus

Non-billable headerICD-10-CM

O35.0 is a non-billable header ICD-10-CM code for maternal care for (suspected) central nervous system malformation in fetus. It cannot be billed on its own: choose one of the more specific child codes below. This code also requires a 7th character before it is complete.

This code requires a 7th character

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.

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

Excludes2 — not included here, but may coexist

The excluded condition is not part of this code, but a patient can have both. You may code both.

chromosomal abnormality in fetus (O35.1-)

Excludes1 inherited from the categories above O35.0

These are not written on O35.0, but they bind it: a note on a category applies to every code beneath it. Billing O35.0 with anything listed here is a denial.

Written on O35 — Maternal care for known or suspected fetal abnormality and damage

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

Other codes that can never be billed with O35.0

These codes carry an Excludes1 note pointing at O35.0. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading O35.0 alone.

Z03.7Encounter for suspected maternal and fetal conditions ruled out

Risk adjustment

O35.0 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code history

O35.0 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Code to one of these instead O35.0

10 child codes. Green means billable.

Related codes at this level

Codes that share O35. If O35.0 is not quite right, the correct code is usually one of these.

Questions about O35.0

Is O35.0 a billable ICD-10-CM code?: No. O35.0 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does O35.0 sit in the tabular list?: Pregnancy, childbirth and the puerperium (O00-O9A), in the block Maternal care related to the fetus and amniotic cavity and possible delivery problems (O30-O48).
What cannot be coded together with O35.0?: O35.0 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above O35.0 (O35) and apply to it just the same.