ICD-10-CM 2027
ICD-10 code for infant post-term
From the official ICD-10-CM alphabetic index entry “Post-term (40-42 weeks) (pregnancy) (mother) › infant”. Page updated September 29, 2026.
About coding infant post-term
The ICD-10-CM code for infant post-term is P08.21 (Post-term newborn).
Within P08.2 (late newborn, not heavy for gestational age), P08.21 is specifically for Post-term newborn. Related codes cover prolonged gestation of newborn (P08.22).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 795 (Normal Newborn, relative weight 0.2022), in MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about infant post-term ICD-10 codes
What is the ICD-10 code for infant post-term?
- P08.21 — Post-term newborn.
Is P08.21 billable?
- Yes. P08.21 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can P08.21 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict P08.21 as a principal diagnosis.
Is P08.21 a CC or MCC?
- No. P08.21 is neither a CC nor an MCC under MS-DRG v44.0.