2027 ICD-10-CM Diagnosis Code O46.91Antepartum hemorrhage, unspecified, first trimester

ICD-10-CM Codes›O00-O9A›O30-O48›O46

ICD-10-CM O46.91
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

O46.91 is a billable ICD-10-CM diagnosis code for antepartum hemorrhage, unspecified, first trimester. 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. The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64). Coders also document this condition as first trimester bleeding. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Early, first or unspecified trimester hemorrhage.

Code Identity

ICD-10-CM Code
O46.91
Billable Status
Yes — Valid for Submission
Code Describes
Antepartum hemorrhage, unspecified, first trimester
Short Description
Antepartum hemorrhage, unspecified, first trimester
Same as the full description in the CMS dataset.
Parent Code
O46.9
Antepartum hemorrhage, unspecified

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO30-O48Maternal care related to the fetus and amniotic cavity and possible delivery problems
CategoryO46Antepartum hemorrhage, not elsewhere classified
This CodeO46.91Antepartum hemorrhage, unspecified, first trimester

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O46.91.

Maternity diagnoses
The Medicare Code Editor detects inconsistencies in maternity cases by checking a patient's age and any diagnosis on the patient's record. The maternity code edits apply to patients age ange is 9–64 years inclusive (e.g., diabetes in pregnancy, antepartum pulmonary complication).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • First trimester bleeding

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to O46.91: its own notes plus those printed at O46 and Chapter 15. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From O46 Antepartum hemorrhage, not elsewhere classified applies to 24 codes
  • hemorrhage in early pregnancy (O20.-)
  • intrapartum hemorrhage NEC (O67.-)
  • placenta previa (O44.-)
  • premature separation of placenta [abruptio placentae] (O45.-)
From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • mental and behavioral disorders associated with the puerperium (F53.-)
  • obstetrical tetanus (A34)
  • postpartum necrosis of pituitary gland (E23.0)
  • puerperal osteomalacia (M83.0)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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 O46.91, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming O46.91: they are not reported together with it, unless the two conditions are unrelated.

  • O67 Labor and delivery complicated by intrapartum hemorrhage, not elsewhere classified
    antepartum hemorrhage NEC (O46.-) names O46.-, which includes this code

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR PRG009
Early, first or unspecified trimester hemorrhage
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Antepartum Hemorrhage

    excessive blood loss prior to onset of labor.

Patient EducationClinical

Health Problems in Pregnancy

A health problem in pregnancy is any disease or condition that could affect your health or the health of your fetus. Some health problems may make it more likely that you will have a high-risk pregnancy. A high-risk pregnancy is one in which you, your fetus, or both are at higher risk for health problems than in a typical pregnancy.

The full article covers:

  • What are health problems in pregnancy?
  • What raises my risk for health problems during pregnancy?
  • Can chronic health conditions cause problems in pregnancy?
  • Can health problems in pregnancy be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert O46.91 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
641.91 Antepartum hem NOS-deliv
Approximate The match is approximate rather than exact.
ICD-9-CM
641.93 Antepart hem NOS-antepar
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About O46.91Overview

What is the ICD-10 code for antepartum hemorrhage, unspecified, first trimester?

The ICD-10-CM code for antepartum hemorrhage, unspecified, first trimester is O46.91 (sometimes written as O4691). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is O46.91 (Antepartum hemorrhage, unspecified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report antepartum hemorrhage, unspecified, first trimester on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does O46.91 group to?

When antepartum hemorrhage, unspecified, first trimester 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.

Who can O46.91 be reported for?

The Medicare Code Editor checks antepartum hemorrhage, unspecified, first trimester against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.

Can O46.91 be reported with a code from O20?

Not as a rule. The Excludes1 note at O46, which applies to O46.91, lists "hemorrhage in early pregnancy (O20.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).