2027 ICD-10-CM Diagnosis Code O40Polyhydramnios

ICD-10-CM Codes›O00-O9A›O30-O48›O40

ICD-10-CM O40
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

O40 is a non-billable ICD-10-CM category code for polyhydramnios, so it cannot be submitted on claims. Use a more specific code from this category instead, such as O40.1XX0, O40.1XX1, O40.1XX2, and O40.1XX3.

Code Identity

ICD-10-CM Code
O40
Billable Status
No — Non-Billable Category
Code Describes
Polyhydramnios
Short Description
Polyhydramnios
Same as the full description in the CMS dataset.
Chapter
O30-O48
Maternal care related to the fetus and amniotic cavity and possible delivery problems

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO30-O48Maternal care related to the fetus and amniotic cavity and possible delivery problems
CategoryO40Polyhydramnios
This CodeO40Polyhydramnios

Specific Coding for PolyhydramniosOverview

Non-specific codes like O40 require more characters. Use one of these billable codes instead:

  • O40.1 for Polyhydramnios, first trimester

  • O40.2 for Polyhydramnios, second trimester

  • O40.3 for Polyhydramnios, third trimester

  • O40.9 for Polyhydramnios, unspecified trimester

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to O40: its own notes plus those printed at 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.

  • hydramnios

Excludes1

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

On O40 itself
  • encounter for suspected maternal and fetal conditions ruled out (Z03.7-)
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

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

  • One of the following 7th characters is to be assigned to each code under category O40. 7th character 0 is for single gestations and multiple gestations where the fetus is unspecified. 7th characters 1 through 9 are for cases of multiple gestations to identify the fetus for which the code applies. The appropriate code from category O30, Multiple gestation, must also be assigned when assigning a code from category O40 that has a 7th character of 1 through 9.
Values for category O40 Fetus Identification
  • 0not applicable or unspecified
  • 1fetus 1
  • 2fetus 2
  • 3fetus 3
  • 4fetus 4
  • 5fetus 5
  • 9other fetus

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name O40, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming O40: they are not reported together with it, unless the two conditions are unrelated.

  • Z03.7 Encounter for suspected maternal and fetal conditions ruled out
    known or suspected fetal anomalies affecting management of mother, not ruled out (O26.-, O35.-, O36.-, O40.-, O41.-)

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical InformationClinical

  • Polyhydramnios

    a condition of abnormally high amniotic fluid volume, such as greater than 2,000 ml in the last trimester and usually diagnosed by ultrasonographic criteria (amniotic fluid index). it is associated with maternal diabetes mellitus; multiple pregnancy; chromosomal disorders; and congenital abnormalities.

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.

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 O40Overview

What is the ICD-10 code for polyhydramnios?

O40 is the ICD-10-CM category for polyhydramnios, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is O40 (Polyhydramnios) a billable code?

No. This is a category header that groups the codes for polyhydramnios, and headers cannot be submitted on claims. Claims for polyhydramnios need a more specific code from this category, such as O40.1XX0, O40.1XX1, and O40.1XX2.

Can O40 be reported with a code from Z03.7?

Not as a rule. The Excludes1 note on O40 lists "encounter for suspected maternal and fetal conditions ruled out (Z03.7-)". 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).