ICD-10-CM 2027 diagnosis code

O40Polyhydramnios

Not billable — use a more specific code

O40 is a header code, so it can't be reported by itself. Choose one of the 4 more specific codes beneath it.

Looking up by condition? See ICD-10 code for Hydramnios, ICD-10 code for Polyhydramnios.

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 O40

O40 is the ICD-10-CM diagnosis code for polyhydramnios. It belongs to block O30-O48 (maternal care related to the fetus and amniotic cavity and possible delivery problems) and chapter 15 (pregnancy, childbirth and the puerperium). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: O40.1 (first trimester), O40.2 (second trimester), O40.3 (third trimester) and O40.9 (unspecified trimester).

Don't report O40 together with the conditions in its Excludes1 note: encounter for suspected maternal and fetal conditions ruled out (Z03.7-).

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

Specific codes under O40

Coding notes

IncludesFurther defines the content of the category

hydramnios

Excludes1Not coded here — never report together with this code

encounter for suspected maternal and fetal conditions ruled out (Z03.7-)

Notes that apply from higher levels

Instructions written at a parent level also apply to O40.

Broader instructions also apply from Chapter 15: Pregnancy, childbirth and the puerperium.

Alphabetic index entries

5 entries

Terms in the official ICD-10-CM index that lead to O40.

Codes whose notes reference O40

Z03.7Excludes1

Code history

2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about O40

Is O40 billable?: No. O40 is a header code. Report one of its more specific subcodes instead.