2027 ICD-10-CM Diagnosis Code O31.42Continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester

ICD-10-CM Codes›O00-O9A›O30-O48›O31

ICD-10-CM O31.42
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

O31.42 is a non-billable ICD-10-CM category code for continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester, so it cannot be submitted on claims. Use a more specific code from this category instead, such as O31.42X0, O31.42X1, O31.42X2, and O31.42X3.

Code Identity

ICD-10-CM Code
O31.42
Billable Status
No — Non-Billable Category
Code Describes
Continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester
Short Description
Cont preg aft vanishing twin syn of one fts or more, 2nd tri
Parent Code
O31.4
Continuing pregnancy after vanishing twin syndrome of one fetus or more

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO30-O48Maternal care related to the fetus and amniotic cavity and possible delivery problems
CategoryO31Complications specific to multiple gestation
This CodeO31.42Continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester

Specific Coding for Cont preg aft vanishing twin syn of one fts or more, 2nd triOverview

Non-specific codes like O31.42 require more characters. Use one of these billable codes instead:

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to O31.42: 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.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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.

From O31 Complications specific to multiple gestation applies to 168 codes
  • delayed delivery of second twin, triplet, etc. (O63.2)
  • malpresentation of one fetus or more (O32.9)
  • placental transfusion syndromes (O43.0-)
From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • mental and behavioral disorders associated with the puerperium (F53.-)
  • obstetrical tetanus (A34)
  • postpartum necrosis of pituitary gland (E23.0)
  • puerperal osteomalacia (M83.0)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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.

From O31 Complications specific to multiple gestation applies to 168 codes
  • 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.
Values for category O31 Fetus Identification
  • 0not applicable or unspecified
  • 1fetus 1
  • 2fetus 2
  • 3fetus 3
  • 4fetus 4
  • 5fetus 5
  • 9other fetus

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Code HistoryHistory

FY 2027AddedAdded to the ICD-10-CM code setEffective October 1, 2026.
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About O31.42Overview

Is O31.42 a billable code?

No. This is a category header that groups the codes for continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester, and headers cannot be submitted on claims. Claims for continuing pregnancy after vanishing twin syndrome of one fetus or more, second trimester need a more specific code from this category, such as O31.42X0, O31.42X1, and O31.42X2.