What is ICD-10 code P04.9?

P04.9 is the ICD-10-CM diagnosis code for Newborn affected by maternal noxious substance, unspecified. A newborn affected by a maternal noxious substance during pregnancy, but the specific substance is not identified or documented. P04.9 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. P04.9 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. P04.9 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. P04.9 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for P04.9?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. P04.9 is a payment HCC under V28 (Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications) but was not retained as a payment HCC under V24. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting P04.9?

This is a non-specific code; attempt to identify the actual substance and use a more specific P04 code when possible Use only when documentation is insufficient to determine the type of maternal noxious substance Because P04.9 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

2026 ICD-10-CM P04.9: Newborn affected by maternal

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupP04.9Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Certain conditions originating in the perinatal period (P00-P96) / Newborn affected by maternal factors and by complications of pregnancy, labor, and delivery (P00-P04)

P04.9

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Newborn affected by maternal noxious substance, unspecified

A newborn affected by a maternal noxious substance during pregnancy, but the specific substance is not identified or documented.

Buddy Insight

Newborn effects from unspecified maternal noxious substances indicate potential toxic exposure where the specific agent is unknown or undocumented.

CMS-HCC V28

Mapped

HCC 137

Drug Use Disorder, Moderate/S...

RAF 0.424

CMS-HCC V24

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ACA/HHS

Mapped

HCC 82

HHS-HCC 82

Varies by metal level

ESRD/PACE

N/A

—

Not risk-adjusted for this model/period.

Not mapped

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

P04Newborn affected by noxious substances transmitted via placenta or breast milk

P04.9Newborn affected by maternal noxious substance, unspecified

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for P04.9 in this effective period.

Excludes 2

Official

congenital malformations (Q00-Q99)
encounter for observation of newborn for suspected diseases and conditions ruled out (Z05.-)
neonatal jaundice from excessive hemolysis due to drugs or toxins transmitted from mother (P58.4)
newborn in contact with and (suspected) exposures hazardous to health not transmitted via placenta or breast milk (Z77.-)

Related Child Codes

Official

P04.0Newborn affected by maternal anesthesia and analgesia in pregnancy, labor and delivery

P04.1Newborn affected by other maternal medication

P04.2Newborn affected by maternal use of tobacco

P04.3Newborn affected by maternal use of alcohol

P04.4Newborn affected by maternal use of drugs of addiction

Includes

Official

nonteratogenic effects of substances transmitted via placenta

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for P04.9 in this effective period.

Code First

Official

any current condition in newborn, if applicable

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for P04.9 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for P04.9 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation that newborn is affected by noxious substance

Clinical signs suggesting toxic exposure

History of potential maternal exposures

Attempts to identify specific substances if possible

MEAT Support

HCC Buddy guidance

Documentation that newborn is affected by noxious substance

Clinical signs suggesting toxic exposure

History of potential maternal exposures

Attempts to identify specific substances if possible

Audit Caution

HCC Buddy guidance

Using when specific noxious substance is documented

Confusing with general perinatal conditions

Missing attempts to identify specific exposures

Using when no substance effects are documented

Common Mistakes

HCC Buddy guidance

P04.89 — Newborn affected by other maternal noxious substances (other specified vs unspecified)

P96.89 — Other specified conditions originating in the perinatal period

P04.19 — Newborn affected by maternal use of unspecified medication

P92.9 — Feeding problem of newborn, unspecified

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is P04.9 an HCC code?

Yes. P04.9 (Newborn affected by maternal noxious substance, unspecified) maps to Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications under the CMS-HCC V28 risk adjustment model, with a community non-dual aged RAF of 0.424. It is billable for payment year 2026.

Coder answer: P04.9 is billable and maps to V28 HCC 137, Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: P04.9
Description: Newborn affected by maternal noxious substance, unspecified
HCC (V28): HCC 137 — Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications
RAF: 0.424
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 137, Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications

0.424

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work P04.9 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for P04.9

For P04.9 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed P04.9 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

Get the V28 RAF + MEAT cheat sheet

One printable page: confirm a code's V28 HCC status, its RAF weight, and the MEAT your note needs to make it stick. Free, no card.

Free PDF. No card. Unsubscribe anytime.

What This Code Means

P04.9 is the ICD-10-CM diagnosis code for newborn affected by maternal noxious substance, unspecified. A newborn affected by a maternal noxious substance during pregnancy, but the specific substance is not identified or documented. P04.9 sits in the ICD-10-CM chapter for certain conditions originating in the perinatal period (p00-p96), within the section covering newborn affected by maternal factors and by complications of pregnancy, labor, and delivery (p00-p04).

Under the CMS-HCC V28 risk adjustment model, P04.9 maps to Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications (HCC 137) with a community, non-dual, aged base RAF weight of 0.424. P04.9 was not retained as a payment HCC under the older V24 model, so V28 introduced or recategorized it during the 2024–2026 phase-in. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

This is a non-specific code; attempt to identify the actual substance and use a more specific P04 code when possible. Because P04.9 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for P04.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This is a non-specific code; attempt to identify the actual substance and use a more specific P04 code when possible
•Use only when documentation is insufficient to determine the type of maternal noxious substance

Clinical Significance

Newborn effects from unspecified maternal noxious substances indicate potential toxic exposure where the specific agent is unknown or undocumented. These cases require systematic evaluation to identify possible substance-related effects and establish appropriate monitoring protocols.

Documentation Requirements

✓Documentation that newborn is affected by noxious substance
✓Clinical signs suggesting toxic exposure
✓History of potential maternal exposures
✓Attempts to identify specific substances if possible
✓Organ system assessments for toxic effects
✓Laboratory studies as clinically indicated
✓Safety assessment and environmental evaluation

Commonly Confused Codes

•P04.89: Newborn affected by other maternal noxious substances (other specified vs unspecified)
•P96.89: Other specified conditions originating in the perinatal period
•P04.19: Newborn affected by maternal use of unspecified medication
•P92.9: Feeding problem of newborn, unspecified