O30.011 vs O30.02

O30.011 (Twin pregnancy, monochorionic/monoamniotic, first trimester) compared with O30.02 (Conjoined twin pregnancy), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 20, 2026 · All releases and sources

Summary

These codes should not be reported together because O30.011’s tabular entry lists O30.02 under Excludes1.

Official rule

What is different?

The conditions named and billing status.O30.011 is “Twin pregnancy, monochorionic/monoamniotic, first trimester”; O30.02 is “Conjoined twin pregnancy”. O30.02 is a non-billable header; O30.011 is billable.

Registry fact

Can these codes be reported together?

No.O30.011’s entry carries an Excludes1 note covering O30.02: “conjoined twins (O30.02-)”. Both may be reported only when the documentation shows the two conditions are unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

Yes.O30.011’s tabular entry: “conjoined twins (O30.02-)”. The note covers O30.02.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

None.Neither entry carries an Excludes2 note that names the other code.

Official rule

Is one more specific?

No.Neither is a subdivision of the other, and neither title is the unspecified form; they describe different conditions within category O30.

Registry fact

Is one a parent or header code?

One is a header.O30.02 is a non-billable header, but O30.011 is not one of its subdivisions.

Registry fact

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Excludes1 — generally not reported together

Excludes1 conflict

O30.011

Twin pregnancy, monochorionic/monoamniotic, first trimester

↔

O30.02

Conjoined twin pregnancy

What we found

No — do not report together.O30.011 carries an Excludes1 note covering O30.02: “conjoined twins (O30.02-)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

What to review

Report one of the two. Both may be reported only when the documentation shows the two conditions are unrelated to each other.

Guide: Excludes1 vs Excludes2 Check these on a claim

Why it matters

An Excludes1 note means the two conditions are not ordinarily reported together for the same encounter, because the classification treats them as mutually exclusive forms of the same condition. The documented exception is when the two conditions are unrelated to each other.

Source / rule

CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a

Official guidance behind these answers

Section I.A.12.a — Excludes1 · applies to: Excludes1
A type 1 Excludes note is a pure excludes note. It means “NOT CODED HERE!” An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition. An exception to the Excludes1 definition is the circumstance when the two conditions are unrelated to each other. If it is not clear whether the two conditions involving an Excludes1 note are related or not, query the provider. For example, code F45.8, Other somatoform disorders, has an Excludes1 note for "sleep related teeth grinding (G47.63)," because "teeth grinding" is an inclusion term under F45.8. Only one of these two codes should be assigned for teeth grinding. However psychogenic dysmenorrhea is also an inclusion term under F45.8, and a patient could have both this condition and sleep related teeth grinding. In this case, the two conditions are clearly unrelated to each other, and so it would be appropriate to report F45.8 and G47.63 together.
ICD-10-CM Official Guidelines FY2027

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

	O30.011Twin pregnancy, monochorionic/monoamniotic, first trimester	O30.02Conjoined twin pregnancy
Billing status	Billable	Non-billable header Report instead: O30.021, O30.022, O30.023, O30.029
Classification	O00-O9A — Pregnancy, Childbirth and the Puerperium (O00-O9A)	O00-O9A — Pregnancy, Childbirth and the Puerperium (O00-O9A)
Definition	Twin pregnancy, monochorionic/monoamniotic, first trimester is a billable ICD-10-CM diagnosis code (O30.011).	Conjoined twin pregnancy is a non-billable ICD-10-CM category code (O30.02).
Excludes1	conjoined twins (O30.02-)	—
Code also	any complications specific to multiple gestation	any complications specific to multiple gestation

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on.

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Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources