2027 ICD-10-CM Diagnosis Code O31.42X5Continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester, fetus 5
O31.42X5 is a billable ICD-10-CM diagnosis code for continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester, fetus 5. The 7th character 5 identifies fetus 5 in a multiple gestation pregnancy. 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).
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for O31.42X5.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to O31.42X5: its own notes plus those printed at O31 and Chapter 15. A note printed at a category, block or chapter applies to every code under it.
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.
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 O31. 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 O31 that has a 7th character of 1 through 9.
- 0not applicable or unspecified
- 1fetus 1
- 2fetus 2
- 3fetus 3
- 4fetus 4
- 5fetus 5 this code
- 9other fetus
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Code History & ChangesHistory
New Code O31.42X5 was added to the ICD-10-CM code set for FY 2027, effective October 1, 2026.
Replacement O31.42X5 replaces the following previously assigned code(s):
- O31.8X25 - Oth comp specific to multiple gest, second tri, fetus 5
Questions About O31.42X5Overview
Is O31.42X5 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester, fetus 5 on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character 5 in O31.42X5 mean?
The final character 5 identifies the fetus in a multiple gestation pregnancy: this code reports continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester for fetus 5.
What MS-DRG does O31.42X5 group to?
When continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester, fetus 5 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 O31.42X5 be reported for?
The Medicare Code Editor checks continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester, fetus 5 against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.
