O31

ICD-10Non-billable category

Complications specific to multiple gestation

Official ICD-10-CM descriptor (FY2026)

Complications specific to multiple gestation

O31 is a category heading, not a billable code. CMS does not accept it on a claim; report one of the more specific codes beneath it.

Excludes2

Not included here. The condition is not part of this code, but a patient may have both, and both codes may be reported together.

  • delayed delivery of second twin, triplet, etc. (O63.2)
  • malpresentation of one fetus or more (O32.9)
  • placental transfusion syndromes (O43.0-)

7th character

  • 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.

Permitted 7th characters

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

More specific codes under O31

Where this code sits

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Source

ICD-10-CM FY2026. Centers for Medicare & Medicaid Services (CMS) / National Center for Health Statistics (NCHS), “2026 ICD-10-CM Code Descriptions in Tabular Order” (icd10cm_order_2026.txt). Download the original file from cms.gov. Public domain (US Government work). Descriptors, billable flags and instructional notes on this page are reproduced from that file without modification. Krasyn adds no clinical guidance.

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