P04.6
BillableNewborn affected by maternal exposure to environmental chemical substances
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is P04.6 an HCC code?
Yes. P04.6 maps to Drug Use Disorder/Substance Use Disorder, Moderate/Severe under the CMS-HCC V28 risk adjustment model.
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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.
MEAT Criteria for P04.6
For P04.6to 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 P04.6 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
P04.6 is the ICD-10-CM diagnosis code for newborn affected by maternal exposure to environmental chemical substances. A newborn affected by the mother's exposure to environmental chemicals (such as pesticides, lead, or industrial chemicals) during pregnancy. P04.6 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, P04.6 maps to Drug Use Disorder/Substance Use Disorder, Moderate/Severe (HCC 137) with a community, non-dual, aged base RAF weight of 0.358. P04.6 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.
Document the specific environmental chemical exposure when available for better clinical documentation. Because P04.6 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 P04.6 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the specific environmental chemical exposure when available for better clinical documentation
- •This code reflects maternal exposure history; link to any resulting neonatal conditions with additional codes
Clinical Significance
Maternal exposure to environmental chemicals during pregnancy can cause developmental abnormalities, growth restriction, and various organ system effects in newborns. These infants require systematic evaluation for potential toxic effects and long-term monitoring for developmental complications.
Documentation Requirements
- ✓Documentation of specific environmental chemical exposure
- ✓Type of chemicals and exposure circumstances
- ✓Duration and timing of exposure during pregnancy
- ✓Clinical effects observed in newborn
- ✓Growth parameters and organ system assessments
- ✓Laboratory studies for chemical-specific effects
- ✓Environmental safety counseling provided
Commonly Confused Codes
- •P04.5 — Newborn affected by maternal use of nutritional chemical substances (intentional vs environmental)
- •P04.89 — Newborn affected by other maternal noxious substances
- •Q89.9 — Congenital malformation, unspecified (malformation without chemical cause)
- •P05.9 — Slow fetal growth, unspecified (growth restriction without chemical cause)