O00.529 — Unspecified cornual ectopic pregnancy with intrauterine pregnancy
Is O00.529 billable?
Yes, but O00.529 will trip a Medicare edit. O00.529 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, CMS lists O00.529 under Medicare Code Editor edit 20, “Unspecified code” — meaning a code specifying laterality (right, left or bilateral) exists in the same family. On an inpatient claim this triggers the edit, because CMS holds that there are very limited circumstances in which laterality cannot be documented.
O00.529 at a glance
| Code | O00.529 |
|---|---|
| Description | Unspecified cornual ectopic pregnancy with intrauterine pregnancy |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| FY2027 change | New in FY2027 |
What Medicare edits apply to O00.529?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name O00.529 directly.
A code specifying laterality (right, left or bilateral) exists in the same family. CMS holds that there are very limited circumstances in which laterality cannot be documented.
Which MS-DRGs does O00.529 group to?
O00.529 sits in MDC 14 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 817Other Antepartum Diagnoses with O.R. Procedures with MCCsurgical
- 818Other Antepartum Diagnoses with O.R. Procedures with CCsurgical
- 819Other Antepartum Diagnoses with O.R. Procedures without CC/MCCsurgical
As a secondary diagnosis, O00.529 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is O00.529 listed in the Alphabetic Index?
The Alphabetic Index lists these routes under O00.52, the nearest indexed parent of O00.529. Use them to find the family, then select the specific code.
- Cornual gestation or pregnancy › with intrauterine pregnancy
- Pregnancy › cornual › with intrauterine pregnancy (single) (uterine)
- Pregnancy › ectopic › cornual › with intrauterine pregnancy (single) (uterine)
Excludes1 — never code together — inherited from Chapter 15
The conditions below can never be reported together with O00.529 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- supervision of normal pregnancy (Z34.-)
Excludes1 — never code together — inherited from O00-O08
The conditions below can never be reported together with O00.529 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Use additional code — inherited from Chapter 15
Report an additional code alongside O00.529 to fully describe the condition. O00.529 is sequenced first.
- code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.
Use additional code — inherited from O00
Report an additional code alongside O00.529 to fully describe the condition. O00.529 is sequenced first.
- code from category O08 to identify any associated complication
Excludes2 — not included here — inherited from Chapter 15
The conditions below are not part of O00.529, but a patient may have both at the same time. When documentation supports it, O00.529 and the excluded code may both be reported.