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ICD-10-CM 2027 diagnosis code

O20.0Threatened abortion

✓ Billable / specificCC — complication/comorbidityMaternity · age 9–64Female only

O20.0 is a valid, billable ICD-10-CM code for threatened abortion. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About O20.0

O20.0 is the ICD-10-CM diagnosis code for threatened abortion. It belongs to category O20 (hemorrhage in early pregnancy), block O20-O29 (other maternal disorders predominantly related to pregnancy) and chapter 15 (pregnancy, childbirth and the puerperium). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within O20 (hemorrhage in early pregnancy), O20.0 is specifically for threatened abortion. Related codes cover other hemorrhage in early pregnancy (O20.8) and unspecified (O20.9).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 817 (Other Antepartum Diagnoses with O.R. Procedures with MCC, relative weight 2.0534), DRG 818 (Other Antepartum Diagnoses with O.R. Procedures with CC, relative weight 1.2942), DRG 819 (Other Antepartum Diagnoses with O.R. Procedures without CC/MCC, relative weight 0.7739), DRG 831 (Other Antepartum Diagnoses without O.R. Procedures with MCC, relative weight 1.1558), DRG 832 (Other Antepartum Diagnoses without O.R. Procedures with CC, relative weight 0.7585) and DRG 833 (Other Antepartum Diagnoses without O.R. Procedures without CC/MCC, relative weight 0.5002), in MDC 14 (Pregnancy, Childbirth and the Puerperium), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

The Medicare Code Editor treats this as a maternity diagnosis, expected only for patients age 9 through 64.

It is on the CMS list of diagnoses consistent only with female patients (the sex-conflict edit itself was retired in FY2025).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 640.03 (threatened abortion, antepartum condition or complication).

Coding notes

Applicable toConditions and synonyms classified to this code
  • Hemorrhage specified as due to threatened abortion

Notes that apply from higher levels

Instructions written at a parent level also apply to O20.0.

› From O20 Hemorrhage in early pregnancy
Includes
  • hemorrhage before completion of 20 weeks gestation
Excludes1
  • pregnancy with abortive outcome (O00-O08)

Broader instructions also apply from O20-O29 Other maternal disorders predominantly related to pregnancy and Chapter 15: Pregnancy, childbirth and the puerperium.

Alphabetic index entries

7 entries

Terms in the official ICD-10-CM index that lead to O20.0.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 640.03Threatened abortion, antepartum condition or complicationapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about O20.0

Is O20.0 billable?

Yes. O20.0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can O20.0 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict O20.0 as a principal diagnosis.

Is O20.0 a CC or MCC?

O20.0 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does O20.0 group to?

O20.0 is used in the MS-DRG v44.0 logic for MS-DRG 817 (Other Antepartum Diagnoses with O.R. Procedures with MCC), MS-DRG 818 (Other Antepartum Diagnoses with O.R. Procedures with CC), MS-DRG 819 (Other Antepartum Diagnoses with O.R. Procedures without CC/MCC), MS-DRG 831 (Other Antepartum Diagnoses without O.R. Procedures with MCC), MS-DRG 832 (Other Antepartum Diagnoses without O.R. Procedures with CC) and MS-DRG 833 (Other Antepartum Diagnoses without O.R. Procedures without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for O20.0?

The CMS General Equivalence Mappings map O20.0 to ICD-9-CM 640.03.