2027 ICD-10-CM Diagnosis Code O20.0Threatened abortion
ICD-10-CM Codes›O00-O9A›O20-O29›O20
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Not Chronic
O20.0 is a billable ICD-10-CM diagnosis code for threatened abortion. 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. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 247 closely related codes. The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64). Coders also document this condition as threatened miscarriage. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Early, first or unspecified trimester hemorrhage.
This medical diagnosis code is frequently used in OB/GYN medical specialties to designate conditions such maternal disorders related to pregnancy.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for O20.0.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Threatened miscarriage
- Threatened miscarriage in first trimester
- Threatened miscarriage in second trimester
- Threatened miscarriage in third trimester
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to O20.0: its own notes plus those printed at O20, block O20-O29, and Chapter 15. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- hemorrhage before completion of 20 weeks gestation
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Hemorrhage specified as due to threatened abortion
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
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name O20.0, its category, or a range that includes it.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Abortion (complete) (spontaneous) O03.9
spontaneous See: Abortion (complete) (spontaneous);
threatened O20.0
threatened (spontaneous) O20.0
Pregnancy (single) (uterine) See Also: Delivery and Puerperal; Z33.1
abortion O20.0
miscarriage O20.0
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Abortion, Threatened
uterine bleeding from a gestation of less than 20 weeks without any cervical dilatation. it is characterized by vaginal bleeding, lower back discomfort, or midline pelvic cramping and a risk factor for miscarriage.
Patient EducationClinical
Miscarriage
A miscarriage is an unexpected loss of pregnancy before the 20th week. Most miscarriages happen very early in the pregnancy, often before a woman even knows she is pregnant.
The full article covers:
- What is a miscarriage?
- What causes a miscarriage?
- What are the signs of a miscarriage?
- How is a miscarriage diagnosed?
- What is the treatment for a miscarriage?
- Can a miscarriage be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert O20.0 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About O20.0Overview
What is the ICD-10 code for threatened abortion?
The ICD-10-CM code for threatened abortion is O20.0 (sometimes written as O200). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is O20.0 (Hemorrhage in early pregnancy) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report threatened abortion on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does O20.0 group to?
When threatened abortion 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.
Is O20.0 a CC or MCC?
CMS lists O20.0 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 247 closely related codes in its exclusion list.
Who can O20.0 be reported for?
The Medicare Code Editor checks threatened abortion against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.
