Polyhydramnios (O40) ICD-10-CM
The O40 code range covers polyhydramnios with 33 ICD-10-CM diagnosis codes. 28 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
- hydramnios
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
- encounter for suspected maternal and fetal conditions ruled out Z03.7
7th Character Note
Certain ICD-10-CM categories have applicable 7th characters. The applicable 7th character is required for all codes within the category, or as the notes in the Tabular List instruct. The 7th character must always be the 7th character in the data field. If a code that requires a 7th character is not 6 characters, a placeholder X must be used to fill in the empty characters.
- 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
7th Character
Indicates that a seventh character is to be assigned to codes in a subcategory.
- 0 - not applicable or unspecified
- 1 - fetus 1
- 2 - fetus 2
- 3 - fetus 3
- 4 - fetus 4
- 5 - fetus 5
- 9 - other fetus
Codes in the O40 Range 33 codes · 28 billable
- O40 PolyhydramniosNon-billable
- O40.1 Polyhydramnios, first trimesterNon-billable
- O40.1XX0 Polyhydramnios, first trimester, not applicable or unspecified
- O40.1XX1 Polyhydramnios, first trimester, fetus 1
- O40.1XX2 Polyhydramnios, first trimester, fetus 2
- O40.1XX3 Polyhydramnios, first trimester, fetus 3
- O40.1XX4 Polyhydramnios, first trimester, fetus 4
- O40.1XX5 Polyhydramnios, first trimester, fetus 5
- O40.1XX9 Polyhydramnios, first trimester, other fetus
- O40.2 Polyhydramnios, second trimesterNon-billable
- O40.2XX0 Polyhydramnios, second trimester, not applicable or unspecified
- O40.2XX1 Polyhydramnios, second trimester, fetus 1
- O40.2XX2 Polyhydramnios, second trimester, fetus 2
- O40.2XX3 Polyhydramnios, second trimester, fetus 3
- O40.2XX4 Polyhydramnios, second trimester, fetus 4
- O40.2XX5 Polyhydramnios, second trimester, fetus 5
- O40.2XX9 Polyhydramnios, second trimester, other fetus
- O40.3 Polyhydramnios, third trimesterNon-billable
- O40.3XX0 Polyhydramnios, third trimester, not applicable or unspecified
- O40.3XX1 Polyhydramnios, third trimester, fetus 1
- O40.3XX2 Polyhydramnios, third trimester, fetus 2
- O40.3XX3 Polyhydramnios, third trimester, fetus 3
- O40.3XX4 Polyhydramnios, third trimester, fetus 4
- O40.3XX5 Polyhydramnios, third trimester, fetus 5
- O40.3XX9 Polyhydramnios, third trimester, other fetus
- O40.9 Polyhydramnios, unspecified trimesterNon-billable
- O40.9XX0 Polyhydramnios, unspecified trimester, not applicable or unspecified
- O40.9XX1 Polyhydramnios, unspecified trimester, fetus 1
- O40.9XX2 Polyhydramnios, unspecified trimester, fetus 2
- O40.9XX3 Polyhydramnios, unspecified trimester, fetus 3
- O40.9XX4 Polyhydramnios, unspecified trimester, fetus 4
- O40.9XX5 Polyhydramnios, unspecified trimester, fetus 5
- O40.9XX9 Polyhydramnios, unspecified trimester, other fetus
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the O40 range.
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.
About the O40 Code Range
Polyhydramnios means there is too much amniotic fluid during pregnancy.
O40 separates the condition by trimester: O40.1 for the first, O40.2 for the second, O40.3 for the third, and O40.9 when the trimester is unspecified. The seventh character identifies the fetus, including an other-fetus option and an option for not applicable or unspecified.
Questions About This Page
How many billable codes are in the O40 range?
Of the 33 codes in this range, 28 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the O40 range classify?
The range classifies polyhydramnios. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
