ICD-10-CM 2027 diagnosis code

Z3AWeeks of gestation

Not billable — use a more specific code

Z3A is a header code, so it can't be reported by itself. Choose one of the 5 more specific codes beneath it.

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 Z3A

Z3A is the ICD-10-CM diagnosis code for weeks of gestation. It belongs to block Z30-Z39 (persons encountering health services in circumstances related to reproduction) and chapter 21 (factors influencing health status and contact with health services). It is a header code, so it can't be reported by itself; one of its 5 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: Z3A.0 (of pregnancy, unspecified or less than 10 weeks), Z3A.1 (of pregnancy, weeks 10-19), Z3A.2 (of pregnancy, weeks 20-29), Z3A.3 (of pregnancy, weeks 30-39) and Z3A.4 (of pregnancy, weeks 40 or greater).

Code first: obstetric condition or encounter for delivery (O09-O60, O80-O82, O94-O9A).

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 Z3A

Coding notes

Note

Codes from category Z3A are for use, only on the maternal record, to indicate the weeks of gestation of the pregnancy, if known.

Code firstSequence the underlying condition first

obstetric condition or encounter for delivery (O09-O60, O80-O82, O94-O9A)

Notes that apply from higher levels

Instructions written at a parent level also apply to Z3A.

Broader instructions also apply from Chapter 21: Factors influencing health status and contact with health services.

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 Z3A

Is Z3A billable?: No. Z3A is a header code. Report one of its more specific subcodes instead.