2027 ICD-10-CM Diagnosis Code Z3AWeeks of gestation

ICD-10-CM Codes›Z00–Z99›Z30-Z39›Z3A

ICD-10-CM Z3A
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

Z3A is a non-billable ICD-10-CM category code for weeks of gestation, so it cannot be submitted on claims. Use a more specific code from this category instead, such as Z3A.00, Z3A.01, Z3A.08, and Z3A.09.

Code Identity

ICD-10-CM Code
Z3A
Billable Status
No — Non-Billable Category
Code Describes
Weeks of gestation
Short Description
Weeks of gestation
Same as the full description in the CMS dataset.
Chapter
Z30-Z39
Persons encountering health services in circumstances related to reproduction

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ30-Z39Persons encountering health services in circumstances related to reproduction
CategoryZ3AWeeks of gestation
This CodeZ3AWeeks of gestation

Specific Coding for Weeks of gestationOverview

Non-specific codes like Z3A require more characters. Use one of these billable codes instead:

  • Z3A.0 for Weeks of gestation of pregnancy, unspecified or less than 10 weeks

  • Use Z3A.00 for Weeks of gestation of pregnancy not specified

  • Use Z3A.01 for Less than 8 weeks gestation of pregnancy

  • Use Z3A.08 for 8 weeks gestation of pregnancy

  • Use Z3A.09 for 9 weeks gestation of pregnancy

  • Z3A.1 for Weeks of gestation of pregnancy, weeks 10-19

  • Use Z3A.10 for 10 weeks gestation of pregnancy

  • Use Z3A.11 for 11 weeks gestation of pregnancy

  • Use Z3A.12 for 12 weeks gestation of pregnancy

  • Use Z3A.13 for 13 weeks gestation of pregnancy

  • Use Z3A.14 for 14 weeks gestation of pregnancy

  • Use Z3A.15 for 15 weeks gestation of pregnancy

  • Use Z3A.16 for 16 weeks gestation of pregnancy

  • Use Z3A.17 for 17 weeks gestation of pregnancy

  • Use Z3A.18 for 18 weeks gestation of pregnancy

  • Use Z3A.19 for 19 weeks gestation of pregnancy

  • Z3A.2 for Weeks of gestation of pregnancy, weeks 20-29

  • Use Z3A.20 for 20 weeks gestation of pregnancy

  • Use Z3A.21 for 21 weeks gestation of pregnancy

  • Use Z3A.22 for 22 weeks gestation of pregnancy

  • Use Z3A.23 for 23 weeks gestation of pregnancy

  • Use Z3A.24 for 24 weeks gestation of pregnancy

  • Use Z3A.25 for 25 weeks gestation of pregnancy

  • Use Z3A.26 for 26 weeks gestation of pregnancy

  • Use Z3A.27 for 27 weeks gestation of pregnancy

  • Use Z3A.28 for 28 weeks gestation of pregnancy

  • Use Z3A.29 for 29 weeks gestation of pregnancy

  • Z3A.3 for Weeks of gestation of pregnancy, weeks 30-39

  • Use Z3A.30 for 30 weeks gestation of pregnancy

  • Use Z3A.31 for 31 weeks gestation of pregnancy

  • Use Z3A.32 for 32 weeks gestation of pregnancy

  • Use Z3A.33 for 33 weeks gestation of pregnancy

  • Use Z3A.34 for 34 weeks gestation of pregnancy

  • Use Z3A.35 for 35 weeks gestation of pregnancy

  • Use Z3A.36 for 36 weeks gestation of pregnancy

  • Use Z3A.37 for 37 weeks gestation of pregnancy

  • Use Z3A.38 for 38 weeks gestation of pregnancy

  • Use Z3A.39 for 39 weeks gestation of pregnancy

  • Z3A.4 for Weeks of gestation of pregnancy, weeks 40 or greater

  • Use Z3A.40 for 40 weeks gestation of pregnancy

  • Use Z3A.41 for 41 weeks gestation of pregnancy

  • Use Z3A.42 for 42 weeks gestation of pregnancy

  • Use Z3A.49 for Greater than 42 weeks gestation of pregnancy

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to Z3A: its own notes plus those printed at Chapter 21. A note printed at a category, block or chapter applies to every code under it.

Code First

The underlying condition named in the note is sequenced before this code.

Notes

General instructions on how these codes are used.

On Z3A itself
  • Codes from category Z3A are for use, only on the maternal record, to indicate the weeks of gestation of the pregnancy, if known.
From Chapter 21 (Z00-Z99) Factors influencing health status and contact with health services applies to 1,425 codes
  • Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed. Categories Z00-Z99 are provided for occasions when circumstances other than a disease, injury or external cause classifiable to categories A00-Y89 are recorded as 'diagnoses' or 'problems'. This can arise in two main ways:
  • (a) When a person who may or may not be sick encounters the health services for some specific purpose, such as to receive limited care or service for a current condition, to donate an organ or tissue, to receive prophylactic vaccination (immunization), or to discuss a problem which is in itself not a disease or injury.
  • (b) When some circumstance or problem is present which influences the person's health status but is not in itself a current illness or injury.

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

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name Z3A, its category, or a range that includes it.

Use Additional Code 1

These codes say to use an additional code from the note, and Z3A is one of the codes named.

  • Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium
    code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.

Patient EducationClinical

Pregnancy

You're going to have a baby! It's an exciting time, but it can also feel a bit overwhelming. You may have a lot of questions, including what you can do to give your baby a healthy start. Taking care of your health while you're pregnant will help your fetus develop into a healthy baby. To do that, it's important to:

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 Z3AOverview

What is the ICD-10 code for weeks of gestation?

Z3A is the ICD-10-CM category for weeks of gestation, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is Z3A (Weeks of gestation) a billable code?

No. This is a category header that groups the codes for weeks of gestation, and headers cannot be submitted on claims. Claims for weeks of gestation need a more specific code from this category, such as Z3A.00, Z3A.01, and Z3A.08.

What is coded first with Z3A?

The Code First note reads: obstetric condition or encounter for delivery (O09-O60, O80-O82, O94-O9A). When one of these applies, it is sequenced before Z3A.