2027 ICD-10-CM Diagnosis Code O43.191Other malformation of placenta, first trimester

ICD-10-CM Codes›O00-O9A›O30-O48›O43

ICD-10-CM O43.191
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

O43.191 is a billable ICD-10-CM diagnosis code for other malformation of placenta, 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 twin placenta. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Maternal care related to disorders of the placenta and placental implantation.

Code Identity

ICD-10-CM Code
O43.191
Billable Status
Yes — Valid for Submission
Code Describes
Other malformation of placenta, first trimester
Short Description
Other malformation of placenta, first trimester
Same as the full description in the CMS dataset.
Parent Code
O43.19
Other malformation of placenta

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO30-O48Maternal care related to the fetus and amniotic cavity and possible delivery problems
CategoryO43Placental disorders
This CodeO43.191Other malformation of placenta, first trimester

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O43.191.

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.

  • Twin placenta

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to O43.191: its own notes plus those printed at O43 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 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 O43 Placental disorders applies to 48 codes
  • maternal care for poor fetal growth due to placental insufficiency (O36.5-)
  • placenta previa (O44.-)
  • placental polyp (O90.89)
  • placentitis (O41.14-)
  • premature separation of placenta [abruptio placentae] (O45.-)
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.

Clinical ClassificationClinical

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

CCSR PRG018
Maternal care related to disorders of the placenta and placental implantation
Default principal diagnosis: inpatient Yes · outpatient Yes

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 O43.191 to ICD-9-CMHistory

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

ICD-9-CM
656.71 Oth placent cond-deliver
Approximate The match is approximate rather than exact.
ICD-9-CM
656.73 Oth placent cond-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 O43.191Overview

What is the ICD-10 code for other malformation of placenta, first trimester?

The ICD-10-CM code for other malformation of placenta, first trimester is O43.191 (sometimes written as O43191). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is O43.191 (Other malformation of placenta) a billable code?

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

What MS-DRG does O43.191 group to?

When other malformation of placenta, 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 O43.191 be reported for?

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

What is the ICD-9 equivalent of O43.191?

Under the General Equivalence Mappings, other malformation of placenta, first trimester converts to ICD-9-CM 656.71 (oth placent cond-deliver) and 656.73 (oth placent cond-antepar). The mapping is approximate, so confirm the match fits the documentation.