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O99.321

O99.321: Drug use complicating pregnancy, first trimester

Billable / specific codeICD-10-CM

O99.321 is a billable, specific ICD-10-CM code for drug use complicating pregnancy, first trimester. It is valid for submission on a claim.

Check O99.321 with the rest of the claim: free scrubber

Excludes2 inherited from the categories above O99.321

Not part of this code, but both may be coded when both are present.

Written on O99: Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium

  • when the reason for maternal care is that the condition is known or suspected to have affected the fetus (O35-O36)

Risk adjustment

No CMS-HCC V28 category: this code does not change a RAF score.

Medicare coverage

O99.321 is named in 1 Medicare coverage policy: 1 listing it as supporting medical necessity. Which one applies depends on your Medicare contractor.

  • A57189Billing and Coding: Serum Magnesium

Code history

Unchanged in every release from FY2024 to FY2027.

Other codes under O99.32

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.