O33.5XX1 Maternal care for disproportion due to unusually large fetus, fetus 1

ICD-10-CM Diagnosis Code O33.5XX1 Reference

ICD-10-CM code O33.5XX1 designates maternal care for disproportion due to an unusually large fetus, specifically identifying fetus 1. The code is an active terminology concept with a parent category of O33.5, and it is classified under the semantic type of Pathologic Function. This reference summarizes public terminology records. 1 3

Plain-language overview

ICD-10-CM code O33.5XX1 represents maternal care for disproportion caused by an unusually large fetus, specifically fetus 1, providing a standardized way to classify this specific obstetric health status. 1

What this code represents

The official preferred name for O33.5XX1 is Maternal care for disproportion due to unusually large fetus, fetus 1, and the terminology record maintains an active status for this diagnostic concept. 1

Code O33.5XX1 is assigned the semantic type of Pathologic Function, which classifies the nature of the concept within the terminology system alongside its official naming conventions. 1 3

Coding details

Within the ICD-10-CM hierarchy, O33.5XX1 is a narrower concept under the parent code O33.5, which broadly covers maternal care for disproportion due to an unusually large fetus. 1

The terminology record includes a published abbreviation for O33.5XX1, formatted as Matern care for disproprtn due to unusually large fetus, fts1, to provide a shortened representation of the full official label. 1

Documentation considerations

The code O33.5XX1 explicitly specifies fetus 1, distinguishing it from other codes in the same category that identify fetus 2, fetus 3, fetus 4, fetus 5, or other fetus. 2

What the sources add

While the National Cancer Institute terminology record defines the specific properties of O33.5XX1, the phecode mapping resource lists this exact code among a broader set of related fetus-specific disproportion codes. 1 2

Both official terminology sources confirm the exact preferred name and Pathologic Function semantic type for code O33.5XX1, establishing consistent metadata across different government vocabulary portals. 1 3

Coverage and utilization context

A Medicare Administrative Contractor instruction document lists related maternal disproportion codes, but the provided excerpt does not contain the exact target code O33.5XX1 or establish any specific payer coverage rules. 4

Sources

1. ICD-10-CM O33.5XX1 terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Phecode 652 · ExPRSweb — csg.sph.umich.edu; accessed 2026-07-27.
3. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.
4. instruction to your Medicare Administrative Contractor (PDF) — cms.gov; accessed 2026-07-27.