2027 ICD-10-CM Diagnosis Code O36.8310Maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, not applicable or unspecified
O36.8310 is a billable ICD-10-CM diagnosis code for maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, not applicable or unspecified. The 7th character 0 shows this applies to a single gestation, or that the affected fetus is not identified. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 817 through 819, 831 through 833. The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Maternal care related to fetal conditions.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for O36.8310.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to O36.8310: its own notes plus those printed at O36 and Chapter 15. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- the listed conditions in the fetus as a reason for hospitalization or other obstetric care of the mother, or for termination of pregnancy
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- supervision of normal pregnancy (Z34.-)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- labor and delivery complicated by fetal stress (O77.-)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.
Notes
General instructions on how these codes are used.
- 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
7th Character
Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.
- One 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.
- 0not applicable or unspecified this code
- 1fetus 1
- 2fetus 2
- 3fetus 3
- 4fetus 4
- 5fetus 5
- 9other fetus
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name O36.8310, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming O36.8310: they are not reported together with it, unless the two conditions are unrelated.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Fetal Health and Development
A normal pregnancy lasts nine months. Each three-month period of pregnancy is called a trimester. During each trimester, the fetus grows and develops. Regular medical checkups and prenatal tests are very important. They can:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert O36.8310 to ICD-9-CMHistory
Code History & ChangesHistory
Replacement O36.8310 replaces the following previously assigned code(s):
- O36.8910 - Maternal care for oth fetal problems, first trimester, unsp
Questions About O36.8310Overview
Is O36.8310 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, not applicable or unspecified on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character 0 in O36.8310 mean?
The final character 0 shows the maternal care for abnormalities of the fetal heart rate or rhythm, first trimester applies to a single gestation, or that the affected fetus cannot be identified.
What MS-DRG does O36.8310 group to?
When maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, not applicable or unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 833, 832, 831, 819, 818, 817, with relative weights from 0.5000 to 1.7586 depending on complications. Higher weights mean higher Medicare reimbursement.
Who can O36.8310 be reported for?
The Medicare Code Editor checks maternal care for abnormalities of the fetal heart rate or rhythm, first trimester, not applicable or unspecified against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.
Can O36.8310 be reported with a code from Z03.7?
Not as a rule. The Excludes1 note at O36, which applies to O36.8310, lists "encounter for suspected maternal and fetal conditions ruled out (Z03.7-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
